I recovered my partner's photos and notes from her Samsung phone when she dropped it and the screen broke.

Spoilers: I had to replace the screen.

I had already flashed Lineage OS on it, but this was not helpful.

I first tried to mount the userdata via ADB shell (via LineageOS Recovery or another recovery), but was unable to. AIUI, the recoveries don't have support for Samsung encryption.

Second attempt was to try to boot to GUI, then control the GUI over ADB using scrcpy. This required USB debugging enabled, but I was unable to enable this.

Final attempt was to buy a replacement screen, and follow a YouTube video to replace it.

This was new to me, but it worked. I needed a kit of mobile phone repair prying tools ($15), the screen ($100) and patience.

I've since enabled backups on my partner's phone. :)