Best an easiest way to paint interior brick wall
Margie: maybe this will help
https://www.youtube.com/watch?v=7Gtw0I6khJ8 very good video for brick painting
A paint sprayer.
Have you considered whitewash? I'm sure you could use a color other than white. It allows you to control how much of the brick shows thru.
We white washed our massive brick fireplace wall and are really happy with the end result. I actually posted our project "Massive brick fireplace wall washwash success"