I pray for your sanity with Supreme Calamitas. Here's a pro tip, HOOK THE ARENA, oh and also calamity adds a feature where if you press the downkey your fall momentum is set to the max, this is absurdly helpful for one of the attacks. Good luck, and I hope your ready for boss rush after.
Use mods like “client side Lag prevention” or “lag remover” using them in tandem boosts performance for **some** bosses. Providence especially, some parts are a little laggy but I went from 30-40 fps to relatively consistent 60 fps
What are your specs? I'm playing with GTX 1080, Ryzen 5 2600, 16GB DDR4 and I'm playing with slow motion. If I turn ON frame skipping then it is a mess.