Indeed, one has to create two separate rclone remotes, one for google drive, one for google photos. Both services will share the storage space bought on google one.
Would have been more convenient to have a single mount instead of two separate mounts, but that's how it is at the moment.
Have a look at union or combine remotes - you can have one mount if this is what you want.
But for this I would not try rclone from 2019 you are using - it is like 40+ releases behind current version. Actually I would not use it for anything:)