This has been happening for about 3 weeks now if I go to an area with no service and loose mobile connection then reenter service area in order too recieve and make calls,text, data I need too enter ##72786#. Even though it will show full bars my phone will act like there's no service I have updated my prl, profile, and been in contact with boost mobile trying too trouble shoot this they suggested I get in touch with Samsung they believe it may have something to do with the August update.
As a process of elimination can you try your sim card in another phone and then another sim card in your phone to help rule out the phone or sim card too.
I'm on the August update with my N10+ 5G and N20 Ultra with no signal issues so I'm not sure it's the update @Donniedark0
Current Phone > Samsung Z Fold³ 5G.