I haven’t been able to make this (Glaive Prime) SP viable since I suck at modding, what to do?

Either you go for full slash (glad might+bane for example) without viral or viral, I prefer viral since I'm lazy. Take out reflex coil and put corrupt charge there and it should be more than fine (power throw vs volatile quick return is a preference, I prefer more range). The thing is whether or not you detonate the throw properly - hold e to charge, throw, heavy attack while it's in the air.