The wifi only gets slow in this way on the desktop and to fix it i have to restart the wifi (i disconnect and connect again via the internet configuration menu on the OS). It is really simple to “fix” but it gets annoying real fast.
You have not uploaded the inxi output but lspci output twice.
I have no solution for you, but you seem to be using rtl8188ee and when I google this I find plenty of complaints about speed. And this is for various Linux distros incl. debian. Looks like a generic problem to me.
I use this wifi adaptor for a long time now and just recently got this problem, it was never a super fast connection but it was a good one, now it lags a lot some times. Maybe i should try getting a new one.