I just made up an ad (in Designer) for publishing in print, and my husband suggested that we need to see how it would look to a colorblind reader. It would be VERY helpful to have that in all the Affinity products!
I do have ColorSchemer Studio, which does have the function of showing how your chosen colors would look to someone with different kinds of color vision problems. But I can't load my ad into it and see how the gradients would look, for instance. Maybe someone has such a program, and I'll go looking for one. But it would sure be great if I could check it within Affinity programs! Maybe you could find a developer who's doing this and pay him to incorporate his product into the global Affinity program.