iPhone X restarting randomly even after replacing battery twice?

I bought my iPhone X refurbished and it was working just fine. After about a month or so after using it, it started to shut off and restart multiple times. When it would turn on, the battery would say 0% even if the battery was completely full minutes before. Sometimes the battery percentage would return to its normal state that i was before, but other times the phone would just repeat this process. I talked to Apple Support after I noticed my battery said it needed "Service." The worker told me that it needed a replacement. This was in the midst of Covid-19 so I opted to wait.

Eventually I took it to a store to replace the battery, thinking that would help. It worked for a few days then it went back to restarting over and over again. I took it back and they replaced the battery again but it did not help. The battery page in the settings still says that it needs "Service." I have tried to factory reset it to see if that would help and I also updated it to the recent iOS.

So what I am asking is, is it worth buying a new phone or does anyone know how I can fix this problem? Thanks.