How to activate boss fights in Boneyard? Already purchased

eggimage

I’ve bought the item but bosses still don’t appear. I googled lots pages and couldn’t find the answer. The wiki only says “toggle it on in the perks menu”, but there’s nothing to toggle for that? Where do I toggle it on and why is it so ambiguous
Thanks

Snackers

First, you need to get the Boss Monsters perk, then go into Settings > Tweaks and toggle Boss Monsters.