The main thing people are upset about isn’t that OneDrive exists or that Microsoft is pushing it. It’s that updates have made it so that OneDrive folder backup is automatically enabled without user permission. Backing up files to OneDrive without being asked to. That is a privacy nightmare.
I personally host my own copy of Nextcloud and use that for anything I need to sync or back up. I have a regular back up job that snapshots the Ceph cluster it uses for storage and copies it to my own NAS box here in the house, which is automatically replicated via a Nebula network (like TailScale or Zerotier but fully self-managed) to an identical NAS at my parents’ house across town.