I'd like to remove spider dungeons, and I've tried to set min and max to all kinds of weird values so they don't spawn, but i'm unfortunately still finding them 😂

Can this be done when just installing the mod via the .jar file?
I tried creating a file in ~/.minecraft/data/betterdungeons/tags/worldgen/biome/has_structure/, but it didn't seem to work.

What version are you on? In older versions, you can disable each dungeon type via the config. In 1.18+, you'll need to use a data pack to override the dungeon's list of possible biomes to spawn in.

I don't have an example on hand, but it would be a very simple data pack - just create a file called has_spider_dungeon.json (or just spider_dungeon.json if on 1.19) in data/betterdungeons/tags/worldgen/biome/has_structure/ that looks like the following:

{
  "replace": true,
  "values": [
  ]
}

This will override the list of biomes Spider Dungeons can spawn in with an empty list, meaning it will not spawn in any biomes.