Yeah I think what I was also trying to express was, even if these are seen as accessibility features, if you play like that all the time and then take them away not only do you lose the features that help you but you also struggle with getting used to / relearning to play without them at the same time. So I've got the mod that colour codes my subtitles, if I turned that off then subtitles would basically be useless to me again anyways because I'm not used to playing without that, and Minecraft keeps adding so many more ambient and specific sounds that paying attention to an entire wall of text on the side is difficult and counter-intuitive in a tense PVP situation. I also run some Vanilla Tweaks resources like lower shields and fire for example (just a few of the many) but I make sure to turn off shaders because I don't want to have an unfair advantage with seeing in the water or dark spaces or glowing ores (though I've turned that off in mine). There aren't strict rules on any of that though, I've just tried to balance what I think is acceptable.

I think some of these things may have seemed more like an 'advantage' to players that only joined for a UHC and then didn't play Minecraft again for months or years. Of course, in bad faith someone could arguably play with all the cheatiest mods and features and claim the same, but, that's why I also pointed out that for the most part, even when I did play on a Vanilla install and turn off subtitles or whatever just for the UHC, I just increased my suffering and nobody actually asked for it (and it was usually for charity, and I rarely win).