Low signal in my Samsung Galaxy Note 10 5G

Yesterday, I bought a Galaxy Note 10 5G smartphone that was previously used but it looks like a new one. I inspected the phone before buying it and everything was alright. However, after inserting the sim , there was a problem in the signal that was too low even though the 4 lines sometimes appear full. I tried almost every method of solving the issue after googling it like restarting the phone, resetting network settings, deeping into the safe mode and manually choosing a network operator. Yet, restarting my phone seemed to work for several seconds but the issue remained. Is there a fix to it ? Keep in mind that when I moved to the city centre, the signal improved significantly (but still not perfect). And note that my previous phone used to have a really consistent signal with the same sim card in all circulstances.