Sims and AMR is like going to school, just theoretical statistics or calculations.
Then using the character in a raid, is like going to work - and learning that everything you learned in school was a waste of time.
Theory and how thing actually plays out in reality - is usually two very different things.
Focusing on sims, or addons to babysit procs and similar, only deteriorate your focus from the things that matter (avoiding fire etc).
Trying out different stat reforges and looking at own logs gives way better understanding than asking any websites.