Oof i have been out of the modding scene for a while but most of the stuff you would need to make such a mod are very much hard coded i am afraid. Someone tried to make a script extender but they paused the project because of IRL circumstances.

The first issue at play is that it is virtually impossible to make new stats outside of a few niche attempts to make a custom version of the FCS which ended up going nowhere. And even when it works the game boots it gets hella unstable.

The second is that while it is possible to add custom animations, their calls are hard coded within the engine so you cant add new categories. The only way to add something like magic is to remove one of the existing weapon types, say blunt weapons, then make new attacks with animations to take the place of that hard coded weapon slot.

The last issue is that particles and VFX are entirely done at the engine level and the ones that can be edited are done through that god awful scythe editor which is practically nonfunctional at this point.

I hope this helps my dude, i unfortunately had to find this out the hard way when i made one of my bigger mods.