Some of this could be attributed to your network masts @Rammy or your sim card could be at issue.
Do these issues happen everywhere or in one place ?
As a process of elimination can you try your sim card in another phone and another sim card in your phone.
A Samsung Experience Store or Samsung Service Centre can run a diagnostic test.
Or if you have a cooling off period take it back and swap it.
🌈 Stay Safe & Stay Alert. 🌈
Current Phone > Samsung Z Fold³ 5G.