I do not know if this suggestion has already been done or not but it will be really nice to get quick desynthesis option.

It seems not very important for most of the classes since stuff cannot stack so we generally do not do a lot of desynthesis in one go. However for culinarian it can be pretty annoying to desynthesis huge quantity of fish. Generally to get cristal for not a lot of gils I desynthesis several stack of fish (100+ fish) and it is pretty annoying to manually do it.

In addition there is not a lot of different items you can get from a specific fish (1-2 different cristal + 1 item) and it could be really useful as QoL improvement to have the option quick desynthesis (like for craft) and it will automatically stop when inventory is full.