In case you are wondering why added suggestion 4:
I do agree that greying out the default date is more important.
Besides, I think that name is pretty understandable already and doesn’t need to be changed.
Really? Forget about being a power user, think like someone who just installed Anki 5 minutes ago and FSRS is enabled by default. “Retrievability descending” is understandable? Really, actually?
Chances are, a new user probably has never even heard the word “retrievability”.