While going the whole hog and tracking down every last relationship for a release is a very good way to get to know your music collection - and probably does make it sound better to you - it does take time.
If a MB contributor is good at making scans of cover art, they can possibly make a valuable contribution, with less tech-headaches, by producing CA ( cover art) scans for releases without them. Even if they just add the minimum required metadata for a release as long as they have contributed the tracklist CA, booklet CA, front CA and a DiscID then all that is available for others yo work from, or even to be machine read by AI in a decade or three.
If someone found this mode of contributing fulfilling they could even come to some agreement with the local second-hand shop whereby they rent a box of CDs for a week, scan and enter the basics and then return and exchange them for fresh CDs.
A low cost, lower tech, more visual way to work towards high quality data.