I haven’t used better vampires but with sacrosanct your powers are stronger when you’ve fed and weakness are less. Vampire lord perk tree is huge and one branch being its hemomancy in mortal form

Even if your a regular vampire you can drain people to unlock new mortal form blood magic. Like blood seed as a damage over time, make corpses explode, a damage over time then explode, profaned sun which is an orb that follows the target. It’s basically a spell that goes “you know what I’m not a fan of everything in that general direction”. Usually my mage vampires only use hemomancy.

You also unlock passives and abilities by draining victims then sleeping, such as gaining a blood potion with each drain (go to markarth to stock up then use night walk (mist form) to jump down to the tavern and sleep), blood seed enhancing damage from other sources, a dash/teleport ability, and more

There’s probably a lot more I missed but the mod page does a better job explaining it

Another mod sacrilege, is what I used years before when I only used the in game mods (this is before AE) and only sacrilege was available

Edit: didnt finish my thought. Sacrilege is good for small changes to vampires