As the title says, the damn thing is nothing but dead weight.
I had it for like 4 years in which it gave me trouble sometimes. It would randomly go into boot loop and I had to use Netinstall to recover it. It was pretty difficult since it wouldn't go into Netinstall mode everytime, I had to keep powering it back up and down several times with reset button pressed and it would eventually show up in Netinstall.

Sometimes, after restarting, it would lose almost all the configuration(static DHCP, VPN users, logs). The only thing that would remain was the port forwarding rules(which sometimes even those would disappear) and the PPPoE configuration lol.

Two months ago I said damn this router and bought an ASUS RT-AX5400. It's not that advanced, but I have to deal with Mikrotik at work just enough to make me sick having to deal with it at home too.
Several day ago, I booted my Mikrotik and wanted to restore it to factory settings. Opened Winbox, went ahead and pressed the button to restore it. Well, here comes the fun part. It went into boot loop again.

I tried these days so many times using Netinstall. I tried different versions of RouterOS(6.45, 6.47, 7.1 but I'm not sure if this one even supports it, since it previously had 6.47). NONE of them worked.
The installation started, I could see "formatting harddrive" and then "transferring..." but after the reboot it still went into boot loop!!
Once I saw it in Winbox like it almost worked, but the IP was 0.0.0.0 and I couldn't access it. After another reboot, again it went into boot loop.

During the previous attempts to restore it with Netinstall when it randomly started boot looping, the thing would work again but for some reason....the old configuration was there! Shouldn't Netinstall wipe everything? How did it kept the old config?

This router was nothing but trouble. The moment you'd tamper with any setting, it was like a russian roulette. The only reason it worked for so long is because I didn't exactly do anything crazy with it.

I don't really understand if you want any help with the device or ur just here to complain?
If you want help, try disabling extra "connected" ethernet interfaces. VPN Clients sometimes like to keep them active.
And I would recommend connecting via IP if possible (first connect via MAC and then set IP).
Also, my experience so far has been that Winbox 4 (BETA) is worse at connecting via MAC than Winbox 3 is. (no clue on that, but sometimes it just throws an error while Winbox 3 works fine)

The reset button on my ac2 feels a little "stiff".
I mean, I did buy that one second hand so I don't know what it's been through, but it works best with a ballpoint pen and A LOT of pressure.

My ax's and a hap lite don't have that issue.

But what the hap lite and ac2 share is that after factory reset they need quite a bit of time until it's usable with winbox. (i usually give it like 5 - 10 mins)
hap lite takes longer than ac2 tho (mine has 7.15 installed cause of some tests)

My ac2 I currently have with me on vacation, and I was able to reset it flawlessly.
The only issue I had was that when connecting through MAC, I couldn't upload another ROS Version as winbox would disconnect during upload.
No issue with IP connection

I had a few Mikrotik device in my LAB with 16MB Storage, that had similar issues and would go into Boot-Loops.
I used the Device with some "Extra packages" installed and Logging.
After some Testing, I was able to Identify that the Device Storage was FULL.

Furthermore, they also entered a Boot-Loop after the 7.14.1 Update.
viewtopic.php?t=206068


I was always able to recover the Device after using Netinstall
But had some Issues, similar to your description, trying to Re-Install RouterOS....
Follow the Instructions online to NEtinstall and maybe use another Computer.

I don't really understand if you want any help with the device or ur just here to complain?
If you want help, try disabling extra "connected" ethernet interfaces. VPN Clients sometimes like to keep them active.
And I would recommend connecting via IP if possible (first connect via MAC and then set IP).
Also, my experience so far has been that Winbox 4 (BETA) is worse at connecting via MAC than Winbox 3 is. (no clue on that, but sometimes it just throws an error while Winbox 3 works fine)

The reset button on my ac2 feels a little "stiff".
I mean, I did buy that one second hand so I don't know what it's been through, but it works best with a ballpoint pen and A LOT of pressure.

My ax's and a hap lite don't have that issue.

But what the hap lite and ac2 share is that after factory reset they need quite a bit of time until it's usable with winbox. (i usually give it like 5 - 10 mins)
hap lite takes longer than ac2 tho (mine has 7.15 installed cause of some tests)

My ac2 I currently have with me on vacation, and I was able to reset it flawlessly.
The only issue I had was that when connecting through MAC, I couldn't upload another ROS Version as winbox would disconnect during upload.
No issue with IP connection

You don't seem to understand...
This router does NOT boot! I cannot configure anything!
Winbox has nothing to do with this. It would work just fine until this problem started few days ago.
The problem is...I use Netinstall to install RouterOS and the router still goes into boot loop mode. I did wait like even half an hour and it would just keep rebooting again and again.

I had a few Mikrotik device in my LAB with 16MB Storage, that had similar issues and would go into Boot-Loops.
I used the Device with some "Extra packages" installed and Logging.
After some Testing, I was able to Identify that the Device Storage was FULL.

Furthermore, they also entered a Boot-Loop after the 7.14.1 Update.
viewtopic.php?t=206068


I was always able to recover the Device after using Netinstall
But had some Issues, similar to your description, trying to Re-Install RouterOS....
Follow the Instructions online to NEtinstall and maybe use another Computer.

The only thing I haven't tried is a different computer, otherwise I tried everything, including different power supplies...
I knew the 16MB Storage was problematic after encountering the first random boot loop, but it would work again after using Netinstall.
This time though, I have used Netinstall so many times and it won't do anything...

The only thing I haven't tried is a different computer, otherwise I tried everything

It`s worth the try...
I had very inconsistant NetInstall experience with my Laptops, Work-PC's ect...
But I found a Fujisu Workstation with onboard Intel Network-Chip that works 100% of the time.

sometimes a simple unmanaged switch between PC and the MikroTik device help to achieve a successful Netinstall

Another random bit of generic advice is to use a new power adaptor that meets the voltage and power requirements of hAP ac². The quality of the output of power adaptors decreases over time as the capacitors in them dry out and lose their filtering capacity.

As for assessment of the state of the router itself, a good guide is the behavior of the USR LED when you connect the power and press the reset button - if it first lights up, then flashes once per second for about 5 seconds, then lights stead again for another 5 seconds, and then switches off, there is a chance that the at least the bootloader is OK; you can try with pressing the reset button before connecting power (which activates the backup bootloader) and pressing it right after connecting power (which activates the primary bootloader). If none of these ways you get the proper sequence of USR LED behaviors, I'm afraid it needs replacement; if you can get to the end of the sequence but the device does not show up in the list of devices in netinstall once you release the reset button, it makes sense to use the dumb switch in between and double-check you have disabled all the other Ethernet adaptors on the PC running the Netinstall.