All you can do is focus on what you can control. Focusing on what you cant makes the game seem unfair (which it is) Dont focus on that adc feeding, focus on what you can build to counter the enemy adc thats getting fed, keep in mind that not every game is winnable but every game can be defeat. Stay positive, its almost better that you dont talk unnecessarily in chat, if they blame you dont respond you only fuel the fire if you do. PLay champs that dont depend on team coordination and wombo combos. For example Khazix doesnt depend on his team as much as Orianna with her ultimate, or tanks that initiate like malphite. I see you play support so its kinda hard. It may sound weird but.
Focus more on champs "Like" these:
and less on champs like
all those champs are good but not in bronze, bronze is about snowballing getting fed and leaving little to no room for the enemy to come back, you need to get your adc fed or yourself fed. Brand is extremely OP in bronze, and he can end up becoming the main ap dmg on your team if you play your cards right (dont be afraid to take kills if you dont believe in ur adc) janna, zilean, and Braum depend to much on your adc and most adcs in bronze have poor positioning thats where tahm kench comes in. Janna is good at peeling but like i said the job is to try to get ur adc fed hard in bronze and janna isnt going to cut it much shes overall pretty passive and has to try extra harder compared to thresh blitz, tahm, brand and morg.