The amount of boosted players in Platinum elo is too high

(Yes, this is a repost from last night. First post was taken down because I stupidly gave enough information for player shaming to happen, which is my fault.)

I'm a support main who plays solo in the platinum elo, and in the last few weeks I've gone from steadily being around Plat 2 and Plat 1 to Plat 5. Out of my last 40 games, I've only won 13. Even though for all of Season 5 and start of Season 6 I've been consistently at Plat 1 to Plat 2. And the worst part is, I honestly feel as though a majority of my losses were well out of control simply because of the skill difference in my teammates compared to the enemy. Although there isn't any footage, going by KDA, ward amount, and damage dealt, you can look through my match history at the losses and see that I'll be playing well despite the team being behind for a majority of matches, but as a support I just simply can't do anything if the teammates are bad enough. And that's true even if I were to play another role as well. Meanwhile, there will be allies and enemies both who will have incredibly low CS despite being in platinum, where people SHOULD be having around 7-8 cs a minute, but instead you'll see about 5 cs a minute being the average in plenty of these games. Or, many allies simply don't know how to pick into or against certain compositions and will instead stubbornly pick a very specific champion because they think the champion is OP but putting the whole team at a inherent disadvantage. The last thing I saw a lot, which used to not be an issue in platinum elo, is people simply don't know how to stay alive in lane. One or two deaths in lane is fine, those are excusable. But normally people would sit under tower and back off when threatened to avoid further deaths, or roam to try and help the team elsewhere. Instead, you'll see players try to consistently 1v1 their fed laner and just keep dying, an issue I last saw in high silver/low gold elo back in season 4.

In all honesty, it feels like there are just way too many people in the mid to high elos who simply don't belong. And these players make the matches hard to enjoy, since they will feed and become a bit of a burden on the team. I'm not sure if I'm just truly that unlucky, or if it's how matchmaking is for solo supports (since most of the other supports will be in premades of varying sizes) or what, but there has to be something done about the allowance of these players to ruin games in such high numbers. I do have one proposal. Why not restrict the difference in rankings allowed for people to group together in premades? As of right now the easiest way to boost someone is to get on a smurf or a higher elo account and get in a group with low elo friends to bring them up in elo elsewhere, but if we restrict the rank difference like it is in Diamond+, wouldn't this help out a lot of people? It would also make matchmaking overall easier since there wouldn't be groups of such varying MMR that it's necessary to match them with a varied team as well.