How to sync a folder on Google drive to android My workflow is as follows:

Photos/videos from my camera's SD card are processed on a PC.
Final photos/videos are auto synced between a folder on the PC and Google Drive using Backup and Sync.
Photos/videos are downloaded from google drive android app to phone.
Photos/videos are used from phone on apps.

I have to do step 3 manually. Is there a way for my phone to download photos/videos from Google drive in the background so that they are available in the Gallery app when I need them.
Phone used: Samsung Note 10
Yes. I use Folder Sync for a very similar workflow. It works fine and I have it running on two devices. Additionally, you can setup up automation for scheduled sync.

FolderSync enables simple sync to cloud based storage to and from local folders

Autosync for Google Drive is another alternative