So I have this glitch with serana and if I tell her to leave or wait she will never follow me again and thanks to her my vampire lord's damage is a joke so I want to know if there is a way to get around this glitch so I can tell her to leave but can get her back a diffrent way.

I fixed this glitch when I remembered that followers will go home if you leave em somewhere long enough.
I rested at my house thinking she would go back to castle Volikhar and maybe I could ask her to follow me then, but what happened was that after about a week of resting she showed up beside me and was a follower again.

Maybe this will work for you too, good luck

If you want a strong vampire lord, be sure to not ask her to follow between Volikhar quests, you can send her right to the next objective, or finish them alltogether.

There is a glitch when you send her away, listen to her response, and you'll know if it bugged. She does not call a cave home:)

I allways find her in Fort Dawnguard, near the dining area. I constantly send her away (sometimes so I can use beastform, but mostly because she insists on standing in the most narrow part of the area we are in) and go back to pick her up there...Sometimes when you say "we should part ways", she will reply "I'll be at fort dawnguard if you need me".

Hope this helps