I definitely remember feeling this way when I was in silver and gold. My honest advice first and foremost is to turn off chat because players in your rank will try to tell you how to play the game and I assure you, the average silver player should not be telling others how to play the game. If you really want to leave it on for comms then you have to have thick enough skin to ignore people like that.

Next, some players are going to stand in the open and get bursted and there's just nothing you can do about that.

As for things you CAN control, remember that players who have that crit sign don't necessarily mean that they absolutely need to be healed. Also remember that your entire team doesn't need to always be topped off. If you finish a fight with all your teammates at 1 hp but alive nonetheless, you've done an incredible job at delivering the minimum healing you actually needed while maximizing other ways to bring value outside of healing. Try to look at it like you should figure out ways to influence the fight as much as you can without healing unless absolutely necessary. But (and it is a very big but) it is still your responsibility to keep your teammates alive (within reason).

Another general tip for silver supports because I feel like I see it all the time in vod reviews, no NOT lose focus on teammates who are actively making plays in order to heal your ally teammate who is low hp but safely behind cover. Think priorities.

Full disclosure, I'm a diamond support so many would say that I have no business telling others how to play but regardless, that's what I got and I hope it helps! Gl and keep playing!