How can I get more signal strength on my iPhone 13 Pro?

I have upgraded from a XR to a 13 Pro. I wish I hadn’t!

The iPhone 13 has lower signal strength on the same network and when the signal is weak (which it is now much more often) calls are

dropped.

Apple, please fix this permanently. I have spent $1000 on a new iPhone and at times can’t even make a simple phone call!