iPhone 12 Mini WiFi Issues

I LOVE my iPhone 12 Mini, except that it fails to provide a stable internet connection to wifi. I have a full network signal in my house because I have a mesh router setup, but the connection on only my iPhone 12 Mini is so bad that I just use cellular data.

However, today, FIDO is down across the nation leaving me with only wifi and no cellular network. And what happens? Wifi is working and completely stable on my iPhone!

So why would wifi work only when cellular is disabled? Sounds like a software issue to look into to me.

iPhone is on the latest firmware 14.4.2