Artwork and waveforms gone

I was operating Rekordbox from an external HD. Database, audiofiles, everything. Blame Apple for not allowing me to expand my internal drive. Anyway: the external HD crashed. Just like that. I didn't have time to back my library up first. I had the drive recovered professionally, and it's all still there.

However: when restoring the library from the new recovered drive, all waveforms and artwork are gone. The rest is still there. What can I do?

I can't restore the library from an older backup, because it had been too long. Nor would i like to re-analyze -> still no artwork then. Reloading tags isn't an option either, since a large part of my collection might be too old or something, because they don't have tags saved, so i.o.w. I would lose all info written in Rekordbox on those, which is practically everything but the file name.

I assume the path for artwork and waveform have changed, and that's causing the problem, but don't know how to correct.

Thank you.

I'm on RB 5.8.5 btw. I don't see any use for RB 6 at this point for my use and would prefer not to go there.