leaving groupchats

so im in this groupchat for a sports team im leaving, and i am tired of receiving these messages. i have already removed myself from tons of the groupchats, but i keep receiving messages. i dont know if the coach is creating new groupchats, or adding me back (i asked him to not include me in the groupchats anymore and he said ok) but i also think it’s possible that apple is glitching and im still receiving messages. but i want to remove myself from the groupchat im currently in and there’s no “leave this conversation” button like there normally is, and furthermore, nobody else can kick me out of the gc, so im stuck getting messages i dont care about and i cant get it to stop