If at all possible, Aternos Team, can you add 'Custom Player Models'?
Mod link: https://www.curseforge.com/min…s/custom-player-model-cpm
Custom Player Models is a mod that allows players to have, well, custom player models, without conflicting with animations supplied by other mods, as well as allowing for more customizable body types and features, as well as eye heights and bounding boxes.
On clients, they can only see their own model, and all else remain the default, while servers with the mod installed allow for every player with the mod to see each other's custom models.