I aplogize if it's been asked before, but I could not find anything with the search.

So after a lot of time spent painting Jabba, I messed up and used a gloss varnish instead of a matte one. Is there a way to remove only the varnish or to make it matte? Could I just apply a few coats of matte varnish on top?

If not I might hzve to strip it completely or learn to live with a very very slimey Jabba ?.

I think your best bet is to apply a thin layer(s) of matte over it (brush or spray), I've not heard of a way to remove varnish without taking the paint with it

Thanks, I'll try that first before going for the nuclear option .

I even read that some people do this on purpose. The gloss varnish is a little bit more robust. So they apply this as base varnish coat.
They then apply the matte varnish. Advantage: You see it when the matte varnish is worn off and you can re-apply. This is something you don't see when you use the matte varnish straight.

I have to admit that I haven't tried this so I can't judge this myself. I use matte varnish solely (testor's dull coat).

So you can tell us your experience with this approach

Should be no problem at all matte varnishing over it . As Whitebubble says a lot of people do it anyway although the benefit of gloss varnish being stronger is probably a myth from the use of exterior varnishes (like wood or yacht varnishes) which are not the same as modelling varnishes.

On the other hand you probably wouldn't have any luck taking off a varnish coat with affecting the paint job.