Watched the entire video, agree with many of your points. Your English is also coming along nicely keep practicing it.
Just to further on your point. It's just as bad, if not I would argue worse for True Solo Q low elo players. The randomness is multiplied to a point where. It doesn't matter how good they play. If the other premade is better than your premade you will outright lose.
I've seen this happen many times, and I can't even offer advice I just have to say "unlucky"
The reason for that is that previously low elo players would work on their solo Q mechanics and rise slowly.
You and I both know this takes time.
Unless you are outright smurfing, No Silver player will begin playing as Plat in a day.
With Dynamic Q a True Solo Q player placed in any sort of premade is now at the behest of that premade for them to beat the other premade on the other team.
A Silver player who's facing a fed enemy premade for ex: Lets say you have a JG go 0-4, Bot duo go 0-7.
A single solo Q mid laner Silver player will not possess the mechanics to beat a fed enemy team especially a premade, even if he is winning they will now just focus their attention to him. This is unfair to ask of low elo players, the whole GIT GUD or PREMADE. They should be allowed individual growth and a chance to rise in Solo Q, but right now they are just entirely punished.