Sounds like the kind of problems I used to have with Century Link.

Also, I’ll have to look it up but there’s an app that lets you see a graphical representation of all of the WiFi signals where you are. There were about twenty of them in my home and a large portion of them kind of overlap each other. Made some setting adjustments in my router and now I’m not competing with everyone else’s signal and my internet works great.

Not sure if any of that helps you. I’ll try and find the name of that app. Might be after Christmas though.