I had the same issue on my 15, but it seems to have been fixed by the last update. It was irritating though and exactly as you described- full bars but constant drop-outs and disconnects. I’m assuming you’re up to date software-wise? Hopefully, 17.2 fixes it for you (early December, hopefully).

Torras 360 case.

Not sure if you’re aware or if you like to use em, but Torras and Ultrglass, as well as a few others, have super easy installation kits where you basically clean your screen, drop the mechanism on top and pull the tab. Similar concept to the ones Apple uses I imagine. I have one on my 15 Pro and it only took about two minutes from start to finish.

Had mine for a couple of weeks now. Running perfect. No issues at all.

Torras Diamond Shield with Torras 360 case.

I love the idea of these folios. I bought one from Nomad a few years ago for my iPhone XR and although it was really nice to have my wallet attached to my phone, in real-world usage, the folio became cumbersome to hold while using the phone all the time. Of course, you can just take your phone off when you’re tired of the case. Also, the top-right corner of my screen protector kept getting scratched by the constant friction of the credit cards pressing against the screen while in my pocket. Hope that info helps.