A lot of the complains expressed in this article are distinctly from the proprietary parts.

Stock Android, and especially stock Samsung, is far from being a free software solution.

A turnkey solution based (almost exclusively, and except the driver blobs) on free software would be to buy a phone running something like /e/. I think they also provide backups.

Of course, stuff requiring SafetyNet (or whatever Google current oppressive attestation system) may not work (though microG makes some of it work).