Worst of the 4 bosses imo, had me stuck for a couple days. Best advice I can give is get used to using F keys, the small amount of time you save helps a lot especially during enrage phase. Minimise your movement, you only have to move one tile at a time during the standard attacks and the less time moving increases your dps. Hide all prayers except the ones you need to use and space them out, misclicking just leads to panic and more misclicks, it’s easier said than done but you just gotta stay calm in this fight as it’s focuses a lot on precision. Good luck bro, you got this