Balanced Astral Smite

As you hit a creature with a melee weapon attack, you summon a barrage of ten lightning strikes and/or astral beams. The target takes 10d10 thunder or radiant damage (1d10 for each beam, you customize the beam’s type.) The target must make a DC 15 CON saving throw for each beam/strike, and takes half damage from that particular projectile. Casting this spell weakens your body and your magic. You cannot cast this spell again until you finish a long rest, and every time you hit with an attack before you long rest, you take 1d6 necrotic damage per level past 5th you cast the spell at plus 1: a 7th level casting would get you 3d6 necrotic damage per hit, a 5th level, 1d6.

At higher levels:

2 extra projectiles shoots down from the heavens for each additional slot above fifth. These projectiles do 1d10 lightning or radiant damage (your choice, see above)