There is a well-known "traditional" equation for results and numbers of ranked stroke play vs. average and tier-up, as posted by Wake here.
Other elements are working, yet not so clearly determined/published by the users:
- credit wins, mostly in tournaments, (?help to advance with less rounds and higher average?),
- match play wins against higher tiers (?drop the average?).
Parts in brackets are my guesses.
Other games like A/S, Blitz, Skins apparently are not involved in this subject.