As title said, I have an idea of making this mod. It will be server-side, of course, because it's datapack. But I think people might not like the idea, 'cuz datapack creator usually don't do mod because it's easier to access or some other reasons. So I'm not sure if anyone would follow.
Also, with limited of ideas. Right now, I only came up with custom brewing, custom item tag that guarantee players to walk on powder snow while wearing it (or maybe turn it into item compoents) and old end main island that stand alone in custom dimension (I can re-create it).
It will definitely be a VERY HUGE project if working solo like I am doing right now.

So... I don't know, just an idea, might be abandon if there's no one follow the project, 'cuz there's no point of making it.

And uh... why and where's the idea came from? I digging in the code while making both mod and datapack. There are something I do wanna custom like the walking on powder snow thing.