Our cat is white, and I wear a lot of black. We have lint rollers in every room - I bulk buy them in Tiger and Primark - one hanging with the keys at the front door, and I keep another in my desk drawer at work. I also wear a pin on my coat which says “cat hair, don’t care”, just in case.
I reckon there's a gap in the market for catflaps with a vacuum around the edge of the frame, or at least a brush that looks like the ones you get in a drive through car wash! Something to take the fur off the cat as it comes and goes through the flap.