I think you should use a DAM instead. I use digiKam and it works really well. When I import photos I create a sub-folder with the YYYY/YYYY-MM - Subject, and rename the pictures to YYYY-MM-dd_hhmmss_ms.ext. Then I tag the photos with as many tags as I want and make sure they're geo-tagged. I then go through and cull the photos with the picker and delete the photos that don't make the cut. All of the metadata is written to a sidecar file, so I never change the actual image file. You might even be able to rename the photos to include a main tag.

ETA:

I recommend DK because you're already talking about touching every photo by hand anyway. DK would seem to make the most sense for the file name changes you want to make. You also mentioned Darktable. While this program has tagging/renaming (DAM) abilities, it's primary use case is as a photo editor similar to Lightroom, but, admittedly with a learning curve. DigiKam is primarily a DAM with photo editing capabilities. Ideally, one would use dK for the DAM, and DT (running in memory mode, or no DB) for editing.

I use the docker container provided by:

steefdebruijn/docker-roonserver

Haven't had an issue yet. But this is running on Ubuntu. Also verify your firewall rules are allowing inbound connections on the correct ports.

Do you have multiple VLANs? Do you have a firewall enabled on the machine? If your laptop and phone are in the same subnet and VLAN (hopefully, if not something is very wrong) then the server and client poth broadcast on a specific port (can't remember right now). They should see this. If not you've got a firewall problem. That's my best guess.