I think I’ve been playing so long that the system only gives me a very small amount of SR in ALL of my roles no matter what the output.
This is like using my bare hands crawling out of a hole.
But when my friend created a new account, they were winning 50 - 75 a win the moment they started competitive and after placements.
A new account always gains or loses bigger amounts for like 10 games or so. It helps get people to their actual skill level faster.
As far as why you gain 15-25, that depends on your performance. If you want big gains you need to have those big games in a row without losing, it will start adding sr in chunks as long as you keep performing better than everybody in your rank.
After you win a few you notice it seems like you get a hard game? You need to win those and basically carry then you will start getting fast tracked out of that rank.
When you can’t win those, you are basically at your elo.
HolyCow said most of it, but I want to point out that once you’re Diamond and above, performance doesn’t contribute to your SR gain/loss. Its mostly the difference between your SR and MMR.
If your SR is higher than your MMR, you get less SR per win. Scales on the difference.
And vice versa.
(Its important to note that the MMR goes up and down too with wins and losses, but at a different rate. Basically the system is trying to have the MMR and SR values converge.)
Also, since you mentioned you are a long time active player, chances are the system has determined your MMR range to a narrower deviation as compared to a fresh account. Hence fresh accounts getting wild SR fluctuations, since the system doesn’t have a clear idea of its MMR range.
So, if you want change, you gotta prove to the system that you deserve a higher MMR by just playing and improving to the point that your MMR starts “catching” up to your SR. Then you’ll start noticing bigger SR gains. Though anything more than 22 SR per win I’ll consider pretty good (on a veteran active account).
You can check out this thread, it may help you understand MMR a little better.
us. forums. blizzard. com/en/overwatch/t/how-competitive-matchmaking-and-rating-works-season-21/468152