Legit Question About Matchmaking

So after reset I climbed through silver right into gold. I was matched with silvers and low gold players while in S1. That's it. I barely stayed in S1.

I got into Gold 5. Immediately the matchmaking diversified and I started getting hodge podge mixes of borderless and silvers with me being the only gold 3/5 matches. These games are absolute cluster fucks.

I plummet over the course of a few days. Winning 1 here or there but for the most part losing every time im matched with borderless teams. I drop to S1.

I play 9 games in S1. Matched with only Silvers and Gold. 9 straight victories. My first game after being back in Gold 5 puts me with 2 silvers and 2 borderless players again. The match was just like the monkeyfests I experienced after promotion before. The borderless are flaming, feeding, diving towers and barely coordinating.

So what fuckin gives? lol Why the hell is the matchmaking going to shit after I get promoted? Isn't the purpose of ELO to separate this shit out?

Highly irritated at this. Is there even an answer out there? Or is this one of those we're all shrugging situations?