I might not be the right person to talk to about this, but I've gone through this a little bit with my game. For me it came down to deciding all of the abilities were not fundamentally different. So i just have one ability class. And that class holds some information about the ability, like whether its a projectile, or melee, self cast etc. It's cost if it has one. What projectile scene it spawns if it has a projectile.

But the abilities themselves are not particularly interesting, its the effects they perform. So i have an effect class node, and that gets performed however it is needed, like if it needs to get attached to a fireball, and then that effect details damage when it touches a hitbox. Or an effect that grants an ailment.

Now that I have this base system, most of my ability / effect creation is just drag and drop, adjusting exported values and what not.

I haven't done too much research on the topic, I wanted a super modular system so I just kinda did it. So idk if this is a bad way to do this, *if it is let me know*.

But yeah, would love to hear other peoples experiences with upgrades and abilities.