[2021] What are good isolation vault Warframes for solo and how should I build them

I personally like to use a Titania with a Corrosive build on her Dex Pixia Prime. The Status won't affect the mechs, but it's unlimited ammo as long as you can keep your energy up.

The Corrosive status works well for doing the bonus bounty after, and just doing the whole mission in Razorwing makes it pretty easy to solo all 3.