How to read DVDs?

I have a USB optical drive connected to my Librem 13 v3, and while I have no trouble getting it to recognize Blu-Ray disks, it really doesn’t like DVDs. Normally I’d fix this by adding in libdvdcss2, but that didn’t work. How can I get the machine to recognize CSS-scrambled DVDs?

Note: I’m not asking how to PLAY them or anything else, just get the system to not choke with an error and acknowledge the disc in the drive.

[UPDATE] Fixed

No, I have no idea why it now works. The drive is a USB drive and worked on a different Linux system, but was having issues with CSS-encrypted DVDs on the PureOS Librem 13v3. Not an application, but at the OS level where I’d get SCSI errors and the drive light would just flash and not recognize a disc was inserted.

To be clear, unencrypted DVDs and encrypted Blu-Ray discs, including UHD, recognized fine. Now they all work and the only thing I’ve done is consistently applied the various updates.