Isn’t Artex just textured plaster?

That should be no problem for Sonos.

How much texture is on the ceiling? Can you post a photo? 
 

Whether or not you will hear height channel effects from the upward-firing drivers is more dependent on if your ceiling is flat, how tall your ceiling is, and how far you will be seated from the Arc.

I’ve used similar stuff on walls, great for hiding poor or damaged sheet-rock.

Not an acoustic treatment of any sort, just textured plaster.

https://infogalactic.com/info/Artex

https://www.qwant.com/?q=Artex+ceiling&t=images