Nowdays i would not recommend Mikrotik device with only 16MB storage size. It limits usability only to base router os + wireless package. No space for another usefull features.
Sure 
but OP asked for basic routing and wifi, nothing more.
If the good Mikrotik guys had placed a USB port on the Ax2 we wouldn't be having this discussion 
.
The right "current" device - on paper - is (IMHO) actually the Ax S (undoubtedly the best bang for the buck), the question is more when it will become as reliable as an Ax2 or an Ax3.
from April 2023
We use the USB on hAPac2's for LTE, so I can say they work. More suggesting it's not a "future-proof" device with it 16MB flash. If they were close in price, I'd go with the hAPaxS since you could skip all the wifi-qcom-ac update process, as they ship with the older wireless package. This works, but does not do Wave2 ("Wi-Fi 5")
Yes, there do seem to be few open issues with them. But whatever issues with the wifi-mediatek exist, they are more likely to get fixed, than wifi-qcom-ac potentially used on an hAPac2...
Now if you can get a good deal on hAPac2, it is a workhorse but you may be back here to help configuring wifi-qcom-ac. The words "netinstall" may be used in the discussion ;-).
And, if you really don't care about USB teathering (and want to review all options). The Audience may also have good deals, and they are best for bridge two Wi-Fi networks since they have 2 x 5Ghz radios. They made an Audience LTE6 version that has the LTE modem, so if willing to get another SIM and don't need top data speeds... that could be another path here.
Audience LTE list price $279.
Not even apples and oranges, more like grapes and water melons.
Id stay away from audience........... never understood its appeal $$$$. I would prefer a separate LTE interface into a 5009 or maybe the new BE wifi router.
I did have my eye on the hAP ax S
its currently $134 AUD + a bit more for postage in Australia.
Does seem to do what i need. And it has a usb port.
Given this is a relatively new device with still some issues in it (see related threads on this forum), you either want to wait to get it until all wrinkles have been ironed out or choose something else if your needs are really short term.
Or get it anyhow and accept there will be some issues at the start (but from what I can see/understand, most is SW related so it should be addressed).
Be aware that the hAP ax S is still arm32 not 64, which is limiting for use of containers should that preference arise. Based on your original requirement description this does not matter.
I notice some mention of issues with the hAP ax S… I think waiting a while for wrinkles to be resolved is a good idea.
A few questions just occured to me.
Will i have to enable usb tethering on router every time i plug in the phone ?
Will i have to enable wifi bridge on router every time i enable hot spot on phone ?
Thank you.
I wondered if there was such a thing as a usb to ethernet adapter that can “also” charge my phone at the same time. And it turns out there is 
https://www.amazon.com.au/1000Mbps-Gigabit-Ethernet-Network-Adapter/dp/B0915TB84Y
https://www.amazon.com.au/Belkin-Connect-Ethernet-Adapter-Gigabit/dp/B0D3FRMNW5
https://www.amazon.com.au/Ethernet-Charging-Thunderbolt-Delivery-Chromecast/dp/B0CNKH5GSG
This would theoretically allow me to use my phone as internet connection to an hAP ax2 via one of these adapters AND keep my phone charged while I’m home.
Does this seem feasible ?
I don't think so, they should be settings that remain "sticky", what has to be seen is whether the moment you disconnect your phone something goes down (normal) and when you insert it again it resumes automatically or you need to re-enable it manually.
In any case most Mikrotik devices have a "mode" button that can be used to trigger the running of a script, so, in the worst case you would only have to press this button.
The question seems to me:
Does your phone support such an ethernet interface converter as output of the hotspot?
No idea, it depends on your phone and which OS it is running, see:
https://superuser.com/questions/1127972/android-usb-tethering-to-ethernet-to-router
I will look at router spec pages for a mode button. My phone has an option in settings for Ethernet tethering just under the usb tethering option. Samsung s22
Thank you.
If I buy a 2nd hand hap ax2 does it matter if the seller doesn't have license paper work ?
Nope. License is embedded in the device.
Thank you
Only as a further clarification, ALL Mikrotik devices have a "reset" button that does pretty much nothing if not during a specific power-on sequence, and that can be programmed as well.
The "mode" button is an added (more convenient) feature, to avoid telling people to press the reset button (that won't normally reset anything, and in some models this button is recessed and you need a pointed object to press it).
I’m going to have a look at a second hand hAP ax2 tomorrow, whats the minimum I can do to check its ok before I pay for it ? Maybe login with winbox and look at some mind of self test page ?
I'm not aware of any sort of self-test page. It can be assumed to be pretty much working if it boots and you can connect to it.
There is always some possibility of fried ports or some sort of internal damage, but with used stuff that's kind of hard to rule out. Even though you hear about various hardware problems on this forum regularly, they're actually really rare. Obviously the problem ones make it here...)