let me adress your claims
"VAC sucks and that's a fact because it's easy to avoid being banned. I am 33 and I have an older account, still seeing cheaters on regular basis despite never cheating my self. Ever, in any other game and having this account for god knows how many years."
Answer: I am also an older player playing since 1.6 and I still do not see almost any cheaters in MM but that is just me and I can not argue with your experience
"If VAC was good then there would not be A REQUIREMENT for online tournaments to run a 3-rd part anti-cheat. Come on, touch grass... If you don't get more than 10 reports a day you don't get checked or overwatched, so unless your cheat is the first google search you can rage hack for one game every single day of your life on one account and never get banned.
People do it, some run multiple accounts to play all day long and just rage."
My answer: I believe this exist but again I can not say how many cheaters there are though again I doubt that there are that many. But since I do not see them, its hard for me to believe this. Also bro I am interested in what you have to say but most people will just ignore what you have to say if you type things like "Touch grass". The external anticheat is needed when you want there to be a 0% chance of people cheating. In MM VAC is sufficient catching most cheaters but it can/should be improved IMO.
"Also, it's not a skill issue, it's simple math issue - if you are solo you will be under your actual rank because those who play in stacks will be over their actual ranks. That's in CSGO, that's in any other ranked game. You will loose more than you otherwise would if matches were fair and square with all random players."
My answer: This is a "skill issue" though I agree that the problem exist. I believe that soloQ players are at a disadvantage. " if you are solo you will be under your actual rank" only true for some people. I soloqued to global quickly and easily and I am still there. How can I be "below my real rank"?. SoloQ people will get the rank that they deserve by playing and stacks do not affect that a lot. If you deserve rankup you should be able to win games by yourself and vice versa = skill issue (most of the time playing good -> rank up). But overall yes soloQ player are at a disadvantage and I think that stacks should only be able to play with stacks. More on this later.
"That's math, that's not skill. Because if it was skill I'd just de-rank and then it wouldn't be a problem - but on any rank it's unfair advantage because from the get-go it tips the scales for winning chances. In theory it should be close to 50-50 but stack vs randoms it just isn't."
My answer: True 100% but if you are skilled and deserve a higher rank you should still be able to win more than you lose. Randoms vs stacks is not fair, but losing to stacks is a "skill issue".
"You enjoying it does not really change the math. With a half decent stack you can win 90% of your games, you can't do that solo ever, not consistently."
My answer: "With a half decent stack you can win 90% of your games,...) True. "..., you can't do that solo ever, not consistently" this again is a "skill issue". Maybe not 90% winrate is not possible solo, but I am running a 78% winrate past 100 (only solo) matches. I have pretty much always been running at least over a 65% winrate in MM while only playing soloque (I have a different winrate when playing with 1 or 2 guys, I never play with a 4-5 stack) so I would call that consistent. Winning is up to how skilled a player is, not if they are playing against a stack AKA if you lose more than normally because you are playing against a stack its a SKILL ISSUE.
Hopefully you understand my point of view and why I agree/disagree with your points. Feel free to make any remarks and ask any questions that come to your mind.