I’ve only left a couple games in my competitive career, neither were intentional. One was a power outage, and I returned and rejoined the game, we even went on to win. Despite this, I had left longer than the window allows and I lost 50 SR. I had never felt so unjustly punished.
Anyways my point is that if you shorten the leaver penalty then people are going to be less inclined to come back. At least make it so that they don’t lose ranking if they come back and win the game.