I do not know how you’re spawning the projectiles and I’m not going to watch a 40min tutorial to find out but it’s a matter of having classes or blueprints in an array and [selecting a random one][1], something like this:
There’s no upper limit on how many you can have, really. It all comes down to maintenance in the end. If you’re going this route, you will want to explore blueprint’s version of inheritance: [child classes][3]
Basically, you would design a parent projectile class and create children based on that, each with different set of rules. The core of OOP.