Again, between AX Lite and AX3 I can get to 400Mbps using 2.4GHz.
So the radio is capable to handle it.
small update.
I have checked the wifi->registration table and see that RX rate tops up at 229Mbps and it is stable there but TX rate tops up at 154.9Mbps and fluctuates from 1Mbps till 154.9Mbps and can feel the fluctuation when eg. watching a video or browsing web
I have an update.
I gave up on the max speed for Apple devices as looks like windows devices (tried with mother board ASUS ROG Strix z790-H WIFI and in mikrotik it shows as RX/TX 500+/500+ Mbps) can utilise it fully. So apple problem. Based on this closing this.
One thing, if someone has similar problem with TX drops, I was getting terrible TX drops (to 1 Mbps)/disconnects. Figured out what it was:
freaking usb dongle for keyboard and mouse that was on 2.4GHz. Didn’t see it on frequency scan cause when I used the frequency the dongle was always disconnected.
Ah yes, keyboard dongles, bluetooth devices, … even microwaves.
They all operate in that same 2.4GHz spectrum.
Glad to see you found the issues 
Yes generally usb3 device can interfere 2.4-2.5GHz spectrum if not properly shielded (like some low cost usb-c to usb-a adapters), doesn’t need to be radio transmitting device in purpose.
I would look at the spectrum and see what was clearer in terms of usage channel1, 6 or 12 ( less other APs).
Sorry to bring this up..
You used this dongle with the original device from the provider and did not have problems?
How did they ignore your dongle, but mktk device could not..
Just looked again at the L009UiGS-2HaxD-IN..
How can it say WiFi 6, when it’s only 2.4G
(After reading..) looks like ofmda is 5Ghz only
But there are 802.11AX improvements in 2.4
https://en.m.wikipedia.org/wiki/Wi-Fi_6
#til
Perhaps someone will come in handy. I have exactly the same problem with Samsung A32. Experisively found that the problem occurs with a bluetooth. When you turn off the bluetooth, everything will work fine. It seems to me that this is a problem in L009xxx, because This phone is working without problems with HAP AC2 in all ranges. To be honest, I’m sorry about the purchase of L009 
.
I think that the L009-IN device has a hardware or software Why is tx power locked at 16 and antenna gain at 4? How to change these settings?.
I have the problem of Wi-Fi speed drop when connecting to Poco X6 Pro and also when connecting to MiBox S.
While in the same situation, I get much better speed from RB951G.
While I expected to improve the speed in the same race
I figured out how to increase the TX-Power.
You only have to choose a country with unlimited domain regularity rules in the Country field, such as the US
Of course, this method does not work on all Mikrotik devices.
For example WAP-AC-LTE-KIT
ATTENTION: in some countries this is highly illegal with possibly heavy fines as a consequence … so proceed at your own risk.