So far, the changes we have tried above are safe and you do not need to undo them if you do not want to.
Is this a notebook computer, not a desktop?
If it is a notebook computer, try:
sudo nano /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf
You should see wifi.powersave = 3.
Change the value to 2.
wifi.powersave = 2
Tap ctrl+o to overwrite, then enter key to save current configuration. Tap ctrl+x to exit the editor.