Two of the recommendations below helped a lot: 0 the z gap for supports and switch away from organic to get more surface contact.
I still had some challenges even after these changes helped a lot - just enough pla in the nozzle mixed with Petg left the resulting model very fragile, so for anyone using an MMU you may consider increasing the amount of Petg extruded between filament changes.
I’ve had similar challenges doing the same.
Two of the recommendations below helped a lot: 0 the z gap for supports and switch away from organic to get more surface contact.
I still had some challenges even after these changes helped a lot - just enough pla in the nozzle mixed with Petg left the resulting model very fragile, so for anyone using an MMU you may consider increasing the amount of Petg extruded between filament changes.
Good luck, and enjoy the challenge!