GraPix
Hey, let's try this simple ways instead if it help:
1- Reset Mobile Network Setting
2-Go to Settings under the Mobile tried turn on VoLTE
3- Turn off "Allow 2G"
4-Change the preferred network type to LTE
If it still does not works then here the last complicated solutions always work for my case:
1-Go to settings, apps, see all apps, click on the right 3 dots show system
2-Tried to find CarrierConfig2, Sim App Dialog, and make sure it turn on
3-Last step are crucial tried to find ImsService and allow network permission-This one always get me failed to send and receives messages if I turn off network permission!
Hope this help, sorry my English is not perfect.
Also, forgot to reminds you that since the Pixel 6 to Pixel 8 generations are always bad with receptions/signals. I got Pixel 7 Pro last year just use a few days have to return since I always got not signals. I recommend saving up some cash upgrade to Pixel 9 much more improvements!