It's been a long time since I played this and this is by far the most infuriating feature I forgot about. In the campaign there's battles you can't see until you walk over them and you're forced to fight them. Is there anyway of editing this out or a mod? I can't seem to get into the campaigns via editor cause I wanted to just straight up delete all those encounters.

It's called ambushes. You are not supposed to see ambushes; that is what makes them ambushes.

If we are talking about Heroes 3, then you can edit the campaigns by extracting them first... you need the MMArchive utility, found here

Open the correct .LOD file under <installation path>\DATA\ and filter for .H3C files; you can then export them, modify as usual with the editor, and import them back... needless to say, make backups

The LOD package with the campaigns for GOG version should either 'H3bitmap.lod' or 'H3ab_bmp.lod'; they both have a copy of the original campaign files, not 100% which one the game gives priority (i guess the 2nd, it's the one for the latest expansion)... anyway you can import the same modified version in both