Years ago, I went through a nightmare with @ATT and swore I would never use them for anything ever again.
Dude at Costco talked me into trying their internet again and I reluctantly agreed. The service is cheaper and faster than what I have, plus the guy was working his first job straight out of high school. He would make a few bucks if I installed the service.
The tech called me about 15 minutes past the end of the two hour install window. I canceled. If they're this bad during the honeymoon, you know it's going to be a bad marriage.
The last time I had AT&T, they botched the service leaving me without phone and internet for weeks. They performed service that I asked them in writing not to perform, then tried to charge me $300 for that service. Legacy monopoly thanks to the US Gov. Awesome.
AT&T immediately started calling me to sell crap like solar panels. They called to confirm the appointment over and over. They made a call about covid that sounded kind of threatening. And then they didn't show.