May I add some support for the Affinity app?
I posted an appraisal of several photo editing apps in a post to the Forums about a year or more ago; all of which I purchased and tested.
In this experiment, and allowing for personal taste, experience and bias, I came to the conclusion that Affinity was a significant step up from Photos and lay somewhere between Aperture and the equivalent Adobe products.
I carried this out because I was a great user of Aperture and sought out an equivalent or better at a reasonable price.
In my view, Affinity has the following merits:
In comparison with Adobe products, it is considerably cheaper.
It lies in capability, as said above, between Aperture and Adobe Photoshop.
It can be added as an extension to the Photos app as well as a standalone product.
NB. Very personal view. And I must state that I have no financial or other interest in this product or any other - which is why I purchased all those I tested. Free trials are fine, but don't give one enough time to assess the app and, in some cases, offer a paired-down product.
Having paid for them all, I can reasonably be excused bias in the financial or publicity areas.
Ian