Yes, Affinity, PLEASE make an awesome brush management system.
Yeah, agreed. Using brushes is the whole way I make illustrations and I use custom and purchased brushes a lot for photo compositing and matte painting. Digital painting has been around for 25 years and it blows my mind that brush management is still so clunky. Even Photoshop only recently added a good brush manager... maybe 2-3 years ago... and only after a third party developer created a plugin that Adobe either copied or bought.
This clunky brush management in Affinity is a major reason I don't just switch permanently from Photoshop.