Does google contact sync also sync the sim card or does it just sync the contacts stored on the phone? So I have this old Galaxy S5 phone that that I'm upgrading to a samsung a51, and I'm also getting a new SIM card that keeps the phone number but doesn't keep the contacts. Do i need to do something extra or does it just work? Or should I use Samsung smart switch?
Like the comments by Andrew T said, you have a few storage options:


SIM card.
Phone.
Google account.


During the saving of the contact, it should give you the option to choose, or there should be a default setting.