Phone suddenly unusable

[TRS-80]

My phone was purchased as KDE Community Edition, but after initial distro-hopping, I settled into Mobian stable.

At that time phone calls would drop some times, but most of the time they did work.  I was more or less happy with it as a daily driver (in terms of a phone, anyway).

4G worked, even VoLTE worked (to my surprise!).

Then, maybe a week ago, I changed a couple things at the same time:

1. I upgraded Mobian to Bookworm.
   
2. I changed my SIM and carrier.
   
3. I may have even bent one of SIM pins in the process (not sure though, maybe not).
   

2. From a T-Mobile MVNO (Walmart Family Mobile) to MetroPCS (now Metro by T-Mobile).

3. Yes I realize this fact makes other troubleshooting difficult if not impossible.

What I did not change:

1. I never changed any firmware from stock.
   
2. I never changed kernel from default.
   

Ever since then, I can barely make phone calls.  They often drop right away, or a few to several seconds into the call.  Some times I can complete a phone call.  But it's basically unusable now.

One thing I have noticed, is that the phone seems to want to change from 4G to 3G when making a call now.

So, I have been reading up on firmware and other things, and I am not sure what I should do next?  Any advice / help will be greatly appreciated.