The biggest problem I have is the randomness of targeting desktop only. The option is only visible in one of the many flows that I can never remember how to fin

The biggest problem I have is the randomness of targeting desktop only. The option is only visible in one of the many flows that I can never remember how to find. Once you manage to actually enable it it randomly reverts back to also targeting mobile. My theory is that it does it when you edit some other parameter of the ad since the edit form is part of the flow where you don't have the option.