>>2056251It's only worth it if it's easy to do.
If you have a 8-9-10 speed HG hub, go for it. You can get a microshift advent gruppo for like $100
If you have a 7 speed freewheel? I wouldn't bother. It's not that nice of a bike, so buying whole new rims for it makes very little sense. However, if you are on flatland I would encourage you to buy a cheap narrow-wide chainring and just do 1x7. It's a pretty good solution for a simple errands bike.
Be mindful of how invested you get into this bike. It's really fun to work on a project but in the end it's just an unremarkable 90's mtb. In my experience, it won't ever really be your dream bike.
