Is a fast recovery diodes maximum reverse recovery time the same speed during its max forward current & Repetitive peak reverse voltage or is it much longer than what was specified?
Which is telling you that if those are critical parameters for you, you shouldn’t be using that particular device. It’s like asking what the 0 to 60 acceleration for a Smart Car is. If you’re asking that question, it’s the wrong car. (FYI, it’s double digits).
if you are using a small diode in a switching ckt and the data sheet does not give switching information, then you use it at your own risk, other batches may differ significantly from the unique one you try in a single prototype.
For a more guaranteed outcome you have to buy from a manufacturer who does list these parameters, e.g. ST.com