I was watching something the other day that said tasting the taste of sweet can start the digestive process because your body is preparing for the calories that are associated with that sweet flavour. Ultimately your insulin will spike even with diet drinks.
From here at about 10:50 - https://youtu.be/YxeBmFTH_vM
I’m sure you will see significant loss regardless but perhaps not as much as without the diet drinks.
Good luck!