I've found restic + rclone to be extremely stable and reliable for this same sort of differential backup. I backup to Backblaze B2 and have also used Google Drive with success, even for 1TB+ of data.
It's fantastic to have so many great open source backup solutions. I investigated many and settled on restic. It still brings me joy to actually use it, it's so simple and hassle free.
It also has extensive support for ignoring stuff and it works very well.
I still use Borg because its policy of expiring older snapshots is more useful for me, but Kopia is extremely solid and I would use it any day if I didn't care that it doesn't actually keep one monthly backup for the last 3 months as Borg does (it decides which older snapshots to keep with another algorithm; it's documented on their website).