Ive been able to write some stuff that I would consider myself proud of but its so inconsistent for me.
Half the time im writing I feel brain dead lol.

The only time im able to really write is in the moment when its feels like its naturally flowing out but that method is hard to improve with, plus I have a lot of periods of just no writing at all (currently in that) . How do y'all find success at this s***

melody then mumble lyrics then lyrics

Depends
Could be writing writing
Could be mumble
Could be freestyle

I mean there's no rules or methods to what works best imo