I have used Siril and for stacking it’s fine but I have to admit Pixinsight is really very good for basically… well… everything (OK maybe not everything but certainly lots of things!). It’s a lot cheaper than photoshop as well!
I was just having a browse and I also noted this program: Starry Night Stacker. I have not tried this one but you can read about it via the developers web page here: https://sites.google.com/site/starryskystacker/home
… it states on the dev page that: “FITS files are not supported. Astronomical cameras that use monochrome sensors with filters are not supported”. Having a look in the supported cameras section it’s principally for DSLR users.
I guess another option is either using parallels or bootcamp (considered desperation for is Mac users ).
Slightly off topic - I highly recommend KSARS and EKOS for mount control, guiding (PHD2 also works on Mac), image acquisition - links:
https://edu.kde.org/kstars/
https://indilib.org/about/ekos.html
Another on the acquisition list is Astro Imager from cloudmakers - https://www.cloudmakers.eu/doc/indigosuite_4.0/astroimager.html
Best,
Mctoot