Custom potion effect using attributes

I'm making my own datapack for a server I'm running to spice things up, and someone came up with the idea of custom potions. I've been messing around with /attribute since the start of the server so I came up with some ideas that seem interesting for potions: smaller and bigger size using generic.scale, faster falling using generic.gravity, longer reach using both player.block_interaction_range and player.entity_interaction_range, that sort of stuff. I've been hearing a lot of things about how much more advanced datapacks can be now in 1.21 but I can't really seem to find any article or video explaining exactly how, and especially not if it's somehow possible to use these attributes as potion effects somehow.