[0] incorrect word/grammar. [1] also not a word. [2] actually a word but don't use it. [3] not correct.
Regrettably, this unfortunate usage of "performant" is common in our field (and on HN) and is already infecting dictionaries.
In this example it seems to be used as computing jargon for "good according to some (unspecified) performance criteria."
Google's (Oxford Languages) dictionary gives a similar definition:
(COMPUTING) adjective: performant: functioning well or as expected. "a highly performant database which is easy to use"
This would seem to be a very poor and unclear substitute for words like "fast" or "efficient" or "reliable" or even "effective."
The google incantation (yielding its definition as a computing jargon term for "functioning as expected") seems to be "performant definition" but "performant" is still a terrible word.