@samsung, This is absolutely unacceptable.. even after so many complaints on Note 20 Ultra WiFI connection issues no usable response is provided. The "turn wifi off and then on" is NOT a solution, it's a disgrace to Samsung brand.. shame on you :\
unplug your modem for 10 seconds, plug back in
network reset: From settings > General management > Reset > Reset Network Settings
BEAWARE THIS WILL UN INSTALL YOUR WIFI AND BLUETOOTH DEVICES AND AFTERWARDS YOU WILL NEED TO RE INSTALL YOUR WIFI AND BLUETOOTH DEVICES
From the phone's quick panel, press and hold the WiFi icon, then touch the gear next to the name of your router, then touch advanced, then MAC address type, choose Phone MAC.
try turning off location.
what is your software version? (settings - about - software info - baseband)
are you on a most recent software? i thought this issue was fixed