Oof. I feel you. On top of tanks who think they can run ten thousand miles an hour and never stop because MANA WHAT’S MANA HAHAHAHA.
I’ve found that approaching people with kindness and humor helps a lot. I was in a low key mythic with a rogue who stood in every gd thing and I just said “rogue ilu but if you stand in a green puddle one more time I’m gonna yeet you off one of these platforms myself” or something to that effect. Most people respond to something like “Hey it’s really hard to heal you when you’re always standing in fire. Could you try to be more careful?” with a “oh sorry my bad” and do better. I know it’s a lot to type esp in a fast-paced dungeon environment. But just… something friendly instead of yelling at them… people are so used to others being elitist and toxic that if you’re kind, they generally do try to be better.
That’s my real advice. My “UGH SAME” advice is to roll a priest and just use the priestly yoink/life grip ability to pull people out of things (dramatically) and then /say “FIRE BAD. STOP IT.” everytime they do it lmfao. Honestly that yoink ability is so cathartic. Some tank goes tearing off and doesn’t notice the three adds the DPS pulled that are murdering you and you just YOINK come deal with this ty 