My teammates keep banning my intended champions :(

Maybe... stop playing OP picks that everyone bans?

If you're last pick, it's natural for them to not risk leaving the potentially broken champ open for their first pick to grab (or even trade).

But if you're doing something out of the oridinary like jungle twitch or ADC bard etc, you can't blame them for banning the champ so you actually use something meta.

if they ban something just to ban it that is perfectly fine (your first pick jinx, sona, vel'koz, etc) then there is an issue.

I had a few teams where somebody was flaming because they banned their champ, who was last pick and a problem (blitz) and the person decided to ban their champ as payback. These games were cancer.... I've never hoped the enemy would end the game sooner.

Avoid champions that are commonly banned - Mundo, Jax, etc..

Surprisingly, Zed is super overpowered (I'm not even kidding, my past two games as Zed I went 20/5 and 17/0) and rarely banned. O/C, you might not like playing Zed. IDK, just play whoever you're comfortable with that ISN'T banned every game.

Also, perhaps not playing Draft when you're on tilt is a good idea.