I posted this as a reply in another forum question but it's worth repeating.
On a hunt from an app to replace Lightroom (which I subscribe to along with PS), I found 'Lyn' - lynapp.com.
I love it. It's robust with tons of good features. I gladly paid $20 for a license.
It allows me to bath rename, flag, star, etc -
also lets you upload to all social media and Smugmug, 500pm.
AND - one of the default menu choices is: "Open with Affinity Photo".
LOVE IT. You can get a 14 day trial.
I no nothing about the developer, have no stake in the company. Just glad it's there and in my applications list.