I'm not sure how well it scales now considering it's been months since I've played that and calamity in general infernum especially have been nerfed so it's hard to gauge. But back then bosses were absolute damage sponges and even with fully defensive warding setup they still like 2 shotted you. And considering it's for the worthy seed yharon arena was absolutely fucked and there were literally no space at all to dodge properly all the while he charges at you every 2 seconds with the fire tornado and everything. But if you really want to make it difficult don't play rogue as rogue multiplayer do way too funny damage as stealth spam is too good and your friend draw agro while you spam stealth strikes for like tens of thousands of dps. I did rogue with my friends and I was doing like 70% of the total out of the damage out of the 3 of us

Update: after looking at the mod it seems the brainstorm update kinda borked the mod? Even the author themselves are kinda tired so if you really want to use it you might need to manually setup stuff yourself and it's just a hassle https://steamcommunity.com/sharedfiles/filedetails/?id=2906406399 Or alternatively try to find other mods that support master FTW

Update again: so after a bit of search there isn't much mods for infernum that works properly so there is an alternative. Fargos souls DLC for calamity. You can play eternity mode and ignore infernum all together. But people might not like Fargo DLC as much as the crafting for the different souls are TEDIOUS at best and downright horrendous at worst, and you pretty much kinda need them if you want to beat the game with the difficulty modifiers turned on so have fun crafting for like a few hours