Help please! Samsung S21 problem

What's going on with the wifi connection? Screen capture: https://streamable.com/bf5rh0

Wifi will connect for 10-20 minutes with no issues. Then, randomly begin this pattern of disconnection, connection, disconnection.

I've tried: restarting phone, airplane mode, forgetting and reconnecting to wifi,intelligent wifi turned off, resetting all network connections on device, restarting router and modem.

All other devices (smart TVs, tablets, and other cell phones) in the home work perfectly with no connection issues, so I can't imagine the issue is with the router.

Any other ideas?