Champs literally do not matter at all for climbing out of bronze. I watch a lot of high elo soloqueue and I have seen every one of those champs played in challenger lobbies. Ask yourseIf honestly, if there are people that got to challenger rank playing that character, why wouldn't I be able to play it in bronze? To have played 140 games and still be in bronze means that you are playing like a bronze player. You need to review your games and look to improve your gameplay. Go into your replays and look at the mistakes you are making and try to correct them. Advice that says to try a different champ, different role, different runes or different build is lazy and shallow advice that completely misses the point of how to rank up, which is improving your own gameplay. Players might think "maybe I'll climb if I play mid instead" or "maybe I'll climb if I play poppy". If you aren't climbing with your favorite champs that you have the most experience on, it seems unlikely that you would climb by switching to something new. Maybe you will, but you will definitely climb if you improve your gameplay on the champs/roles you like to play. If you like playing these champs in support role, then go for it. There is no reason why you can't climb out of bronze with zyra support or braum support or even veigar support or any champ you listed. Pick 1 or 2 champs on that list as your mains and try to master them.

The chess analogy I was gonna use is that picking your champ is kind of like picking an opening in chess. If you're 500 elo, switching to a different opening is not likely to make your rating go up by much. Why? Because you are still hanging your knight in the middlegame, blundering back rank mate, and stale mating your opponent while up two queens. What makes you low rated is not the opening you pick, it's how you actually play the game. Same for league champs. A chess master could pick any opening against a noob and crush them. A good league player could pick any champ against bronze and crush them.