What even happened since Season 3?

Yes, this is something of a whinge, click away if you don't want to hear it.

As a disclaimer, I was diamond 3 in S3, then just kind of dropped out of ranked due to lack of interest. For the last few seasons, I've just been doing my placements for gold+ ranked rewards, and that's about it.

I bothered to get my placements out of the way the other day, so I could duo with a friend and...I did horribly. 3/7. Admittedly, I sort of expected this, since I was just playing full-AD, attack-on-sight, never-back-out Xin the entire time because that trash is hilarious when it does well. I figured I'd be low gold again, but I got placed in Silver 1. And I've done almost nothing but lose, ever since, and I can't even really pinpoint why. This is odd, because I originally got diamond almost exclusively thanks my decision making; I had pretty bad mechanical skill, and still do TBH. I'd pick jungle and mid and show up at the worst time for the enemy team, snowballing myself and teammates.

But I just can't seem to do it anymore. I've noticed, also, that a lot of games seem to just swing, horribly, in one team's favor or another. I recall it being fairly common to see a wild mix of scores within a team, fairly often. Now it seems like the entire team rolls at like 7/3 or better (usually with the jungle or mid being a standout), or is losing inhib tower at 22 minutes because nobody can even break even.

I've also noticed it feels like it's become really easy to predict games just based on picks. I've always played something of a game with my friends, in which they tell me who's on what team, and I take a guess on who wins. I've been doing way better the last two seasons (currently at 7 correct guesses in a row), and I don't feel like it's entirely my doing. It seems like I'm not seeing any crazy, big, off-the-wall plays anymore. Just a lot of straightforward interactions, almost all of which just further the aforementioned teamwide snowball.

I can't believe it took me this long to see it, but I also very rarely click away from the recommended item page anymore. Not entirely sure what to make of this, but I've already been robbed of almost every single semi-effective troll build I used to do a few seasons ago. About the only variety in build I see these days is what order to build items in.

Am I just imagining shit? Can I get tips or something? I haven't actually tried playing seriously in a long time, and, to be frank, this kind of sucks. There's no way I've actually gotten this bad, but if this is actually what ranked play is like now, there really isn't going to be anything left in this game for me except the occasional gimmick duo bot lane with friends and URF mode.

Swear to god if the game mode this weekend isn't URF I'm going to lose my shit.