Looks like I have a winner.

After looking for so long for a replacement for my dearly beloved FotoAlbum software, I think I have now found the winner: It is Tropy, from tropy.org. There's still a few things I have to find out how to handle in the new software, but I have sorted out the importing sequence (and that's actually rather simple) and will be able to keep everything, including my dates. There will be some more tests to make sure everything will be in the new place as it should be, but then I should be fine with the new software.

Here's a screenshot of the current small test run:

Another thing to take a look at, and figure out, is the lists of controlled vocabulary that can be linked up with tropy, and then choose appropriate ones. 

But I'm really, really happy that it looks like I'll be able to shift everything to the new place! It's currently 84,654 images in the database, and while not all of them are fully equipped with keywords and a description, enough of them are to make migration in any other way than one big database export, tweak, and import a nightmare.

All the other programmes I've looked at were either not able to import my things (or, to put it properly, making the migrationary tweak was too complicated for me), or they were cloud-based with very limited storage space (we're looking at more than a terabyte here already, so 50 GB free will just make me snort and move on), or really pricey. Or a combination of several of the above. 

I will keep you updated on my progress!