Slow Wi-Fi can come from nearby devices, not just the connection.
Many wireless accessories, microwaves and cordless phones use 2.4 GHz, as do many Wi-Fi networks; USB 3.0 devices can also affect nearby frequencies.
The guide suggests separating devices, moving accessories away from the computer, and restarting the router.
Wi-Fi at 5 or 6 GHz may be faster and less congested, but has shorter range and passes through walls l…
https://en.hacks.gr/argo-wi-fi-oi-syskeyes-konta-sto-router-mporei-na-prokaloyn-paremvoles/