With Thirsting Blade, Life Drinker, a Stength of 20, Dual-Wielder with a Lance, riding on top a mount, that gives you 3 attacks a round, you can be 10 feet away from all creatures when you do these attacks (making almost no opportunity attacks against you, so the risk is low), it's still broken. Especially if you take the feat to get the Dual Wielder Fighting Style.
That gives you 2d12+1d6+10 necrotic damage for 2 attacks, with low risk, and a fairly high bonus to hit, and 2d12+1d6+5 necrotic damage as a bonus action. In a turn, that's an average of 62 necrotic damage. It's definitely not super OP, but is powerful, as it only takes 2 Eldritch Invocations, a feat, and a spell slot for Hex.