I've been having an issue with my Ubuntu 20.04 laptop where it disconnects from wifi from time to time. If I wait a minute it will reconnect, or I can do it myself, but it lasts long enough to pause video if I'm watching one, which is a problem.
After some investigation tonight I figured out that when my laptop's DHCP lease expires on wifi, it stops, then reconnects, instead of planning ahead. So I used the router admin interface to give my laptop a static IP address! Not sure if this will solve the problem but static IP's don't have leases that end.