Is 2kg static cross-load dangerous for a carbon frame?
Opinion, but a frame bag won't cause any problem for a normal bike frame.  If it were an ultralight hillclimbing bike with no paint or something specialist, then I'd worry.
If you're concerned about fretting of straps on the clear coat, get some of those clear frame-protection stickers and apply to the frame under any retention straps for your bag.  Also cinch velcro straps down firmly.