1. As you're trying to solve the problem with syncing it will help if you rethink how it's actually working. There is no Google Drive direct link between your phone and your computer. Your phone is connecting to your online Google account and your computer is also connecting to your online Google account. The syncing process is centered on the Google Drive service that's part of your online Google account. It's stored and managed on Google's servers. So changes to files and things using your phone's Google Drive app are transferring/syncing with your online Google account, and changes to files and things you do on your computer are also done to your online Google account.
Since you're apparently also having issues with Google Maps accuracy (question 2) that could point to an issue with your cellular and/or mobile data connectivity. Google Maps relies primarily on GPS but it also requires mobile data connectivity so have you checked into your carrier access?
With WiFi disabled and only mobile data enabled, is your online access pretty stable? Approximately how fast?
Try using your web browser app and go here:
https://speedof.me
and do a bandwidth speed test. What are your download, upload, and latency speeds?
Is the cellular connection icon in your S20's Status bar showing how strong a signal your phone is receiving?