@Carlo240
Good day!
Are you trying to say:
The speed of the adapter is very unstable, starting from 30m/s, then dropping to 1m/s at the end?
Did it happen all the time and may I know how can you recover the speed, rebooting the computer, or disable and enable the adapter?
If possible, please also try to use the following driver to have a look: https://static.tp-link.com/2019/201911/20191129/Driver_RTL_8192EU_TL-WN822N_V4.zip
(V5 used the same chipset);
And how to use the driver: https://www.tp-link.com/support/faq/920/
And you could also try to change the wireless setting of the 2.4ghz of the main router, such as channel 11, channel width 40mhz;
Thank you~