Honestly, what I'm learning is that you need to play mid to climb in low elo.
You can win 51-55% of games playing any other role and will slowly climb. It will require luck though. I've failed every promo series I've ever tried (even with free wins from previous failures) if I don't play mid. End up getting teams that feed and from the top lane (or bot lane when I used to play top/adc) I just can't influence the map early enough to stop the feeding. I don't know why I seem to get such worse teams in my promos, but I do. So going slightly ahead in lane and getting a 51-55% chance isn't good enough when I win 2 to get in to promos then lose 2 to lose the series for the first 90 games before I finally get through. I don't want to play it that much.
I swapped to mid and won every promo series from Bronze 1 to Gold 4 in flex queue. Just influencing the map earlier made that difference. I went to solo and tried top again, and what do you know, I started incredibly strong in my placements and regular matches then have gone 0/4 on my two promo series. I prefer top, but I just can't seem to win there. Whereas mid is where you can carry from in bronze-gold pretty reliably.