-speed +res mia any useable?

I think she's viable, yes. 37 speed is still a pretty decent number.

You have different options:
-Use her as an enemy phase unit. Her mixed bulk is pretty decent and 37 speed is still difficult to double for a lot of units, especially common armored units like Zelgius(and BK), Hector or even Amelia. You can use her default Flashing Blade with the Phantom Speed seal. This way her Flashing Blade speed comparison puts her at 47 speed(this is with Phantom Speed 3), then Quick Riposte as her B skill to make sure she doubles. You will have a unit with pretty decent mixed bulk and still not easy to double that will proc a 3-cooldown special with +10 damage.

-You can also run a Fury/Flexible B skill(Vantage/Swordbreaker would be my choice)build. With Fury her resistance is 32, pretty decent to activate Ploys on most melee units, so take that into account as well.

-You could even run a Distant Counter build with Wrath and QP Moonbow. She would get +20 damage to her special and also 52 attack which is still pretty high.

-If you really want to use her as an offensive unit rather than a defensive one, I guess you could run Life and Death/Desperation. She would have 42 speed(45 with +3 speed sacred seal) so she still has plenty of speed.

Congrats on pulling her! I hope this helped!