ArtRage is "painting", Designer is "drawing", even though he can paint it too.
Definitely not compatible, everyone uses their native format. The only way of exchange and cooperation is through image export.
My needs are different than yours. I'm only a little interested in making digital work look like traditional media. ArtRage does a good job of that, and is simple to use. But I haven't used ArtRage at all after working w. the Affinity apps. There are some vendors who offer natural like brushes for AD/AP, such as DAUB and Frankentoon. You might look at their websites to see if the offerings are what you might like to use. Affinity's built in brushes are OK, but really just an introduction to what one can do.
