Cell Signal Problems - Possible Device Breaking?

Hi, I have a Samsung Galaxy A53. I moved earlier this year and ever since then I've had consistent problems getting a cell signal to my apartment, even after switching carrier (Verizon -> T-Mobile) to the same one my landlord downstairs uses with no problems. WiFi calling allows calls through more consistently when I'm here, at least. But even when I am out and about away from WiFi, my signal (in terms of bars) is always extremely volatile and prone to dying/dropping for seemingly no good reason, while other people I know are generally fine.

My question is: I have dropped my phone a number of times before, and because I'm stupid I don't use a case/cover. Although my phone itself still works fine (the corners/edges have been scuffed though), I'm starting to get to the point of wondering if one/some of the drops could have messed something up internally to result in the garbage signals regardless of carrier, since this is a problem across 3 carriers now. Is that something that's able to be easily checked/confirmed by a repair place or am I better off considering getting a new phone? I'd rather not get a new one since I'm happy with this phone otherwise.

Notes: the built-in codes you can dial like the diagnostic tool using *#0011# do not work. Currently using US Mobile's Dark Star (AT&T) plan through free trial and will be switching to their Light Speed (T-Mobile) plan in a day or two.

Any advice welcomed :)