Yo I wanna do all swords but the 1.16 version is way harder of random seed no structures and I already have jellysquid for 1.16 can I just play on that and submit for 1.0-1.15 once I have all the swords except netherite?

bruh no u cant

Why not I feel like it would be just like doing a no structures run without actually turning off structure generation. As long as i dont touch a ruined portal or some shit I think I should be good right?

1.16 has different seeds than 1.0-1.15 and obviously you can't do that bc it's a different version. the purpose of having a category split is because there is a specific purpose of playing in that version. As an over-exaggerated example, why don't I play on 1.16 and submit to 1.9-1.15, I just won't trade with piglins at all.