keep the library on an external SSD that is mounted to the same path on both machines
sync images and sidecars with external drive and look for updated xmp art startup. If it is only every 3 months startup delays probably doesn’t matter. I actually use a simple rsync script for syncing.
make a softlink so that the path to images is the same
use SQL to modify the path in the database
Best regards
Till
Edit: Here some sqlite command I was using in the past: