I think the one you're talking about is Versusia's stage variant of "Zero Point".
I don't recall what the unlock condition was but try going into the arcade mode, and defeat the hidden Versusia boss at least once. See if this unlocks the stage for you.

To fight Versusia in arcade mode, you need to secure at least 1 round win with your SBA/SSBA against the final boss, either Beezlebub or Lucilius (also, not sure if this is needed but just to be safe, try not to lose any round during this final boss fight). Once condition is met, you'll fight one extra hidden battle with a super buffed up Versusia. Beating her will unlock a profile badge (one badge for each of the normal route and true end route), and probably the stage unlock.
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Either that, or check if you have extra episodes in story mode. Versusia was added after release so unsure if her story counts towards the completion percentage.

I have already completed the episode 82 and i also beated versusia once in the arcade mode, but i still cant unlock this scenary

Guys i finally did it, the thing is i completed the episode 82 in hard mode, apparently you have to complete it in easy mode to unlock it, weird, but ok, thanks!