As much as your frustration is justified, I wonder why don’t you team up with someone together to play team ranked or just play 1v1?
While having to meet certain conditions to play ranked (with randoms in team) might be a good idea, it would also drive some people OFF the game.
For example my friend and me, we started playing aoe4 last season only (not been playing since beta) and jumped RIGHT into ranked, no quickmatch or customs.
So we queued for 2v2 together and got placed in platinum, then kinda quickly improved, learned the game while playing it and ended up in Diamond in the end.
We had played aoe3 excessively over multiple years together before in 2v2, so obviously we wouldn’t wanna waste time playing casual quickmatches but play for sweating instead, also get beaten by good players a lot of course.
Had we had to play lets say 50 matches unranked before being allowed to play ranked, we would most likely just have refunded aoe4 after finding out about it.
The best way to go about this would probably be to make up certain conditions to be met, before you can play with your non placed (!) account with randoms in team, team ranked.
The system shouldn’t keep you off playing full premade queue.
Very honestly, if you are playing better than the elo you are placed at, you will eventually rise a lot in rank, until you reach the elo that you belong to, even with random team mates.
It is very frustrating though at times, I agree.
Whereas the lower your elo is, the easier it is to climb for a good player.
At some point you will get team mates who are as good as you or better than you.
When my friend didn’t have time, for example, I played 2v2 with randoms from mostly plat 2 until diamond.
Some matches your mate doesn’t have the best game (who always has a good game right?), but often times you also get carried, it evens out eventually.
It’s just that the negative experience tends to be remembered by the human mind, whereas the positive one is forgotten about.
Keep trying dude, stay positive and rank up my friend 
It’s crucial when playing ranked, to try and NOT look at the negative experiences, just ignore them.
Work on your skills and game knowledge and eventually you’ll rank up and also will get more and more better team mates, the game will become more fun, but also tougher oponents.
What helped me personally, whenever a game had been either close or a complete stomp, I watch the replay and analyze both teams, what they have been doing and how and what their timings were.
It’s also very interesting to see what builds other people use, especially the players who felt strong in the match.
Sometimes you learn something surprising and can use it in your collection of BO ideas or tricks.
Edit:
Almost forgot to agree with your point:
Ranked is the mode where you are supposed to be sweating and tryharding and be extra (!) sportsmanlike.
I could never understand either, why (some) people wouldn’t respect this unwritten law and use ranked to joke around, make people angry or start flaming etc.
The fun of ranked should be winning of course, but mostly TRYING the hardest to win.
The fight is the goal. Improve, get better, play against better players, that’s the fun, right?
A defeat shouldn’t be a reason to get angry, but to watch the replay and improve.
If it was not you but the guy you played with who was the actual reason for the loss, then just let it go.
Anyone can have a bad day/match however he’s trying. Sometimes it’s just bad luck.
Go on and win next one!
Again, more often it’s your own play which didn’t let you win the game.
Keep watching the replays and see where the win-potential was lost.
Most of the times you’ll lots of space to improve for yourself and probably even serious mistakes in game decisions, which in the heat of the moment you couldn’t avoid.
Often times you’ll see moments in the replay where the enemy has very little army, whereas you had a lot but didn’t scout enough and didn’t punish the booming enemy.
Keep it up bro!