"Higher MMR solo q experience is generally worse off because I consistently match with 4 stacks who are abusing mechanics such as Azrael's Teleport glitch, Makutu's cell cheese, and it's just boring, unbalanced, and the added misery of seeing your rank plummet afterwards when all of the above is a problem can be frustrating".
Another thing regarding this is the fact that there are not enough high mmr players online at a given time so matchmaking can create balanced matches. What this xbox trueskill matchmaking does in this situation is that instead of having two full teams of the same skill level it creates matches by looking at team averages.
1 high trueskill player is going to be put with 3 average to low trueskill players while the enemy team will get all decent to even it out.
Matches are balanced because both averages on paper but that translates to 1 team which is really underskilled compared to the other resulting in really draining and pointless games to play. You can solo but after hitting that sweet spot of trueskill your matches will get balanced out like this and your only option to have a decent experience is to play in a group with people who you can rely on.
I agree with all the points you mentioned Amber. I suggested a lot of similar points on the discord but it appears the discord functions only as a medium for the community to rage about soloq rather than a medium to provide feedback even if its critical feedback.