[warp]

My experience is the same, git-annex just doesn't work well with lots of small files. With annexes on slow USB disks, connected to a Raspberry Pi 3 or 4, I'm already annoyed when working with my largest annex (in file count) of 25000 files.

However, I mostly use annex as a way to archive stuff and make sure I have enough copies in distinct physical locations. So for photos I now just tar them up with one .tar file per family member per year. This works fine for for me for any data I want to keep safe but don't need to access directly very often.