I am experiencing the same problem with unlocked note 10 plus on Verizon. My 1 + 7 pro has no issues here at my house, but the note 10 seems to always be barely hanging on to his signal. Hopefully a software update can fix this soon.
Still having issues on Verizon going into 3G and 1X even after a recommended software reflash at a repair center. I wish someone at Samsung could just say when this software fix will happen. I am ready to return my 2nd Note 10 Plus if not. As great as the phone seems to be, it isn't much of a device if it cannot consistently connect to calls or data!
My note 10+ has had signal issues from day one. Switch unlocked one twice with same result before I returned it and got the verizon one. Still has the same issues. I've tried everything but nothing works. My note 9 works fine in same areas with same sim cards. I dont want to switch but I cant have a phone that doesnt work right. I wish samsung would fix the issues.