90% of times it's the other lanes fucking it up, not me.
Then I fight unkillable enemies because even if we kil them once or twice it's over.
You know I carried myself mostly through solo queueing into very high skill bracket (before ranked matchmaking) by playing gankers or junglers, especially Bounty Hunter and Ursa. Though Ursa stops working once you get out of lower skill brackets, sounds like you could prob jungle him and tear your way through the bads.
You should try to get a solo lane if possible, either mid, jungle, or a sidelane if you have a jungler, this gives you a good level advantage even if you have feeding sidelanes. Whatever you pick and play as soon as you get to level 6 or so, stop giving a shit about your lane completely and just roam around killing people. Even the worst of dota pubs will see opportunities to pad their KD and go in if you set up a play, even if just to killsteal you.
If you aren't playing with a team or at a high skill level with dependable teammates (this does not go hand in hand) there is no reason to pick support. Just roam around clearing empty sidelanes and neutrals to stay competitive in farm and XP, and by level 6 you should be forcing enemies to TP into sidelanes and causing 3vs3 or so skirmishes. Know the limits of your hero to make ballsy plays and you can guarantee a pub stomp victory within 10 minutes by giving your team the level advantage and momentum.
Static thinking of lanes, roles, "if only they stop feeding their lane, I'm winning mine!!" and all that crap is low tier, scrub play. If a lane is struggling, might be worth it to go kill them before they get too big, and restore Team Morale. Fairly sure anyone advising to "stay in mid and farm for 30 minutes then solo win the game" just watched a smurfing pro player's stream, or is just making shit up and can't break 200 GPM with freefarm.
Being aggressive, but knowing your limits so you don't feed, is definitely the best way to climb in Elo if you are a solo player. Be tHe PlayMaker.