Haven't really seen any toxicity caused by this. For the final story dungeon, I was healing for the first time and we wiped like 4 times to the first boss cause most didn't know how to properly move through its main mechanic. The tank tried to show us and we eventually learned it and got past the boss.

If you're worried about not being allowed to learn or have anxiety about making a negative impression, I recommend finding a newbie-friendly FC (or just a general friendly FC, usually most people like helping and supporting others in this game in my experience) and running the dungeons with them. Letting the party know its your first time or even just that you might struggle with some bosses. Or actively asking for advice. It can be a hurdle to have the courage to communicate, but it can easily lead to more positive experiences.