Unstable internet with Archer TX20U Plus
My computer has a 2.4Hz wi-fi, thus I was experiencing packet loss on my recent acquired ISP (moved home).
According to ISP, its an issue with 2.4Hz interferences, thus I bought a AX1800 Archer TX20U Plus to go for 5G and avoid interferences.
The internet is even more unstable, If I ping google 10 times, 7 will be around 5 and 8ms, but other 3 will go up to 300ms. Also each 2 minutes one packet will be lost.
I tried every single thing I read on internet. First of all removing the option of USB turning power source off (because at first USB would get disconnected every 2 minutes), updated drivers, put on USB 3.0, changed the IEEE configs etc.
I have a ROG STRIX B360 -F GAMING motherboard and Windows 10.
You are right. If there are so many other Wi-Fi networks nearby, then your own Wi-Fi will always be affected.
And when there are so many neighboring Wi-Fi networks, then the chances you might find some unused channels in the 2.4 GHz or 5 GHz bands are close to zero, I suppose. Some Wi-Fi Analyzer programs or apps will grade the available channels and show you which channels are the least used and most used, but I don't know how accurate this is. Besides, many Wi-Fi routers are on the "Auto" channel setting anyway, so the occupancy of the bands will frequently change.
I think the only way to avoid those conflicts would be to upgrade to hardware that supports the 6 GHz band (both, the Wi-Fi router and the Wi-Fi card). But Wi-Fi routers that support the 6 GHz band are not cheap.
I live in an apartment building as well and there are about 20 neighboring Wi-Fi networks that show up in my computer's list. However, I have not yet noticed another 6 GHz Wi-Fi network showing up, other than my own. Therefore, at present I still have the 6 GHz band all to myself. 
You are right. If there are so many other Wi-Fi networks nearby, then your own Wi-Fi will always be affected.
And when there are so many neighboring Wi-Fi networks, then the chances you might find some unused channels in the 2.4 GHz or 5 GHz bands are close to zero, I suppose. Some Wi-Fi Analyzer programs or apps will grade the available channels and show you which channels are the least used and most used, but I don't know how accurate this is. Besides, many Wi-Fi routers are on the "Auto" channel setting anyway, so the occupancy of the bands will frequently change.
I think the only way to avoid those conflicts would be to upgrade to hardware that supports the 6 GHz band (both, the Wi-Fi router and the Wi-Fi card). But Wi-Fi routers that support the 6 GHz band are not cheap.
I live in an apartment building as well and there are about 20 neighboring Wi-Fi networks that show up in my computer's list. However, I have not yet noticed another 6 GHz Wi-Fi network showing up, other than my own. Therefore, at present I still have the 6 GHz band all to myself.