1. Open Magisk, Magisk Hide, and tick the check box next to Google Pay. Proceed normally through the following steps after doing so.
2. Force stop Google Pay, clear app data/storage.
3. Open a root file manager
4. Using root file manager, find /data/data/com.google.android.gms/databases directory
5. Select a file called db.dg and chmod the permissions to 440, save and make sure it in fact saves
6. Reboot and set up Google Pay.
This should get you set up in no time without a need for modules or advanced user techniques. Hope it helps!
Edit: People seem to really dislike this method for some reason, so just throwing out there it seems everyone else recommends the SQL editing. This method worked for me, but YMMV and everyone else hates it