Tldr; don't use a pixel 7Pro .. it hands over networks poorly
I had to get rid of my 7Pro on T-Mobile for this reason. I think I got a bad device (open box from Best Buy) but even before I loaded graphene on it, it did not stay on 5G in known high signal areas, and the switchover between 4G and 5G was stinky but I only had it for a day before I wiped it and flashed grapheme. I was mostly on WiFi so I didn't notice how crappy the cellular performance was until later... Lots of modern problems and network dropout as it seemed to fail those handoffs.
I tried new SIM cards, using an eSIM, you name it. I had a OnePlus 11 that was 5G+ 5 bars side by side with the Pixel 7Pro with poor signal strength, stuck in 4g LTE etc. Swapped SIMS, lots of troubleshooting with TMobile techs doing network resets, etc. Nothing worked.
I had read that the 7Pro has some known modem issues related to 4g-5g handover, etc.
I flashed it back to stock Android and tested it for a week and the issues were not specific to graphene.
I got rid of the 7Pro and got a (New) 8Pro and now it all works fine. Hands over networks just fine etc.
YMMV