I’ve been buying physical media and want to save digital copies for SD card. I had no issues with my CD for music but DVDs don’t work.
I have an optical drive that I plug in and it works. VLC with libdvdcss installed through Discovery failed. I tried MakeMKV but it doesn’t detect the optical drive.


I use makeMKV as a Flatpak and never had to change any of the permissions, although it’s true that F’atpaks have restrictions.
But I never tried it on my Steam Deck.
Maybe OP has another computer he could try MakeMKV on.
My thought is because of USB access. It wouldn’t allow that by default. But if OP has a computer with a built in drive, it’s worth a test.