@Miriam I use them on Windows, but the do have Mac support.
I don't own Designer, but have used it. It's wonderful, I cannot use Inkscape for the life of me. Their video tuts are extremely helpful, easy to understand, and free. I didn't buy it because I don't need vector right now, and want to focus on other things.
I just bought the Affinity Publisher, it supports indesign files which is a big plus. I've yet to do too much with it, but it's a dream. Will make publishing a breeze.
I haven't used Affinity photo.
Doesn't look like Publisher is available for the Ipad, but the other two are and on sale for $10. $25 for mac or windows right now.
Edit: To me Affinity design is better than Illustrator, but that could be a personal preference. And I've never really used Adobe InDesign, so I can't compare.