I do not use an object store for public access in Discourse, due in part to the migration being a one-way door and also not needing it; in my case, it would be serving that data from the same storage, just with another VM to manage. I use an object store only as a restic backup target, done outside Discourse.
Discourse backups with thumbnails but without images, combined with host-level backups of uploads, backed up with restic on host, means that those limitations are, as far as I know, irrelevant.