I haven't seen it mentioned anywhere, but the application bundle on macOS hints at a pretty robust scripting API using Javascript. The functionality doesn't seem to be exposed from what I can see in the app.
In the "first look video" Ash Hewson (Affinity CEO) says "“we’ve also got full scripting capability coming very, very soon” (at 21:33). What's said in the video is that this - and some other developments - will be part of "free" and not dependent on subscription. https://youtu.be/UP_TBaKODlw?si=lJkRZ6l8ekQRF43R&t=1293
