Been with Verizon and in the same area for over 16 years. The last three weeks our S9 would drop a call or we could not hear the person on the other end here at our home. Traded it in for 5G S21 and same thing but worse. The phone will at times show an "X" for signal, or a single "G", then bounce to 4G or even 5G, regardless the drop call and lack of hearing a caller is the same. Numerous calls to Support services provide no resolution. Run through the same troubleshooting list. I was suppose to be recently transferred to another "expert" hung up after an hour on hold.
Sorry to hear you have been having issues after so many years of loyalty. We'll gladly do what we can to assist. Are the concerns only happening while at home? Indoors our outdoors? If so, is this happening when WiFi is on or off?