Do you mean the Language:
There is no setting for that AFAIK, either per project or globally.
Yes I mean language. Too bad there's no preference for it. Kinda annoying to flip the button and select every single time.
I didn't see anything already on ArcGIS Ideas related to this. Maybe worth posting.
Thanks for looking. Related https://community.esri.com/ideas/8722-change-expression-parsers-within-python
Yup - I ran into that one when searching for what you're currently requesting. So in Pro 2.4, there will be access to make these changes through Python. But that doesn't set the default, and you wouldn't want to use Python to change that every time as opposed to just using the drop-down