Sigh, First mistake not helping your adc survive to kill the tank and being alone too much.
Two, volibear and lee are bruisers not a tank. Volibear is more juggernaut and lee sin diver. Build does not factor in role naming.
Three version A, you have 4 other teammates, once you kill the adc/mid you should be working with your team for your adc to get through the lee then voli. Going by what you say you're not working with your team. Yes solo queue can be nightmarish, but if you can't nicely work with your team ofc you aren't going to get the win
Three version B, why are you doing a 1v1 vs a tank? You should be telling your team you'll kill either the adc or mid then they can focus on peeling the rest of their team off of you and the adc since 2 damage dealers is better than their 1 damage dealer.
Overall it just sounds like you played the game without caring for your teammates and translating your advantage to the rest of your team. Even if you were badly matched with others, if you worked up a strategy for them to follow you could win. Also I highly doubt you could die in one-shot with proper positioning and itemization.
Kills don't matter if you can't play the later parts of a game right.