I am usually the worst player (among the 10) a discussion about matchmaking

So I just reached level 30. I've been playing this game for a few months maybe 2 or 3. I am getting better at the game but no matter how much I improve I am always the worst player (among the 10 in the game). I frequently get matched up with silver and/or gold players on my team (which means there are probably some on the other team also). My KDR is awful. Just a quick glance at my last 17 games (10 wins) I have a total KDR of 45 kills 111 deaths. True 6 of those games I was playing support but anyone can tell that this is a really bad stretch. However, this is not just a recent trend. I have ~130 wins and probably 280 games in normal summoner's rift. I have less than 50 where I finished with a KDR over 1 (only 4 of which are within the last 30-40 games). I don't mind playing support so I do play more of that role but it's seems pretty clear to me that every time I play I'm getting matched up with opponents and team mates who are vastly better than me.

I've had 10+ games losing streaks, and I'm way under the 50% win margin that people generally see. I think once I get to playing ranked games where the system may get a better feel for me as a player then I may see some better matches.

I know a lot of this is just mistakes that I make along the way. Every game I make a few errors and obviously cutting down on that and becoming a better player will allow me to hang with silver and gold players. I wouldn't say that I'm losing motivation to play, but I do think the games would be more fun if I wasn't getting blown out every time.

Note: I mostly duo with my brother who has actually been playing for only a month or two (a little less than me) although he reached level 30 a week before me and he's probably slightly better than me and usually the 2nd worst player on the team. On rare occasion (not within the past 3 weeks) we've played with my brother who is (or has been) gold V. Infrequently we play with a silver player who is a close friend and has a lot of experience in the game.

I guess my question is should I just solo for a while until the game gets a good feel for where I am as a player before I start duoing again. It's not like I never solo but typically I'd rather play with my brother.

If you made it this far thanks for reading, sorry for being wordy.