I can't syntergize with EZ

Your title should be "I can't syntergize with bad Ezreals". In which case, it would be the same for every adc played by a bad player xD

do you know what you do?

you pick either braum blitzcrank or thresh

these supports will make adc's go ham for kills

omg op I agree with you, I usually 100% lose my lane when I'm supporting an Ezreal. Oh and good Ezreals do not exist in Silver ELO

Ezreal is a hard champ. Hopefully you know what his abilities are if you want to set things up for him. He is a kite type of champ that's based on skillshots and auto attacking is really not his thing. So when you go in, go in with him full mana and make sure his abilities are all up. If you can't set things up, usually ask jg to gank then make sure someone is getting kills. If you are full health and full mana but he has no mana, don't look for an all in, it won't happen with ez. The best he can do is try to auto attack but against a crit champ I'm doubtful that will help. Also, he should try to trade early in game and when their low, you should go in.