MMR gain rework support

So this made me think a bit.
I haven't played in about a year because life caught up. Bought tickets for TI but since that got canceled I had some time to start playing again.

Last time I played I was ranked around the higher end of legend. Had to recalibrate, won some, lost some, ended up being crusader (??). I've always played hard support.

One thing I've known for years, and which became painfully obvious in the current bracket: support has too little impact on the game to consistently gain mmr, even if you're good. You can't compensate for a griefing position 1 or 2.

Just got out of a game with a position 1 who had no clue what he was doing. Auto attacked creeps which pushed the lane, killed my pull camp and then complained to me that he cant lane because its too pushed. Kindly asked him to not kill pull camp and all will be fine, which resulted in him muting me (??). At that point I kinda knew this was a lost cause. Still tried my best; stacking and warding overall, trying to set up smoke kills and pressure map when it seemed fit. But to no avail.

This isn't just this game, it feels like atleastttt half of the games is like this. My question: what would be a good way to rework the mmr system? Or am I forced to learn to play mid untill I get out of this hell hole?