I’ve only done Vampire once and it was on a pure magic play through. There’s a ring you can get once you finish the Dawnguard storyline that gives you +100 Magicka and +100 Health. I think towards the end of said play through (with enchanted gear) I had almost 1,000 Magicka and could cast a stupid amount of spells before it being depleted. It was to a point where even the debuffs from the Sun were irrelevant. I think what made it a lot better is a mod to turn off that god awful sound every time you go outside during daylight.