I do exactly that on my FP4 from time to time. I have installed termux (available both in the Play Store or FDroid) on the phone which gives a regular linux terminal. Inside termux I installed rsync, so I can run the following on my phone:
rsync -a --exclude=thumbnails /data/data/com.termux/files/home/storage/dcim/Camera/ ingo@192.168.178.11:/home/ingo/PhonePhotoBackup/
That copies over all photos to PC that I haven’t synced yet and doesn’t sync back photos from the PC that are not on the phone. If you want different behavior, I guess rsync does support it with the right combination of parameters.
For me it’s working fine over WiFi (and an ssh server on my linux PC).
IIRC I had to allow storage access for termux once and needed to find the correct path to the internal storage that termux can read. Over adb it would be /storage/emulated/0/DCIM/Camera but that wasn’t accessible from termux.
Haven’t looked into networking via USB cable (beyond “adb push/pull”) so far because I never had to. Might be possible, too, if WiFi isn’t stable enough.