Hi there!
In my opinion, on the mac, Affinity Photo works nicely together with Apple Photos. May be not perfect, but still good.
At the moment I am testing Affinity Photo on windows.
I always install "Faststone Image Viewer" on my windows PCs. It has a basic tool chest, but most important, as a organizer it works well with Affinity Photo. Just add Affinity to Faststones list of editors, and you open the image in Affinity from a short cut.
Affinity Photo. - Priced very nicely! Power packed with capabilities!
Faststone Image Viewer - Free for home users. Basic functionality.
Perfect couple. Powerfull, easy to use, cheap.