F3 menu shows in main menu

That is intended. Refer to the 25w31a changelog:

• The debug screen is accessible by pressing F3, as before

• It can now be accessed from everywhere in the game, not only when in a game world

Thank you for your report!
We are tracking this issue in MC-300118, so this ticket is being resolved and linked as a duplicate.

That ticket has already been resolved as Works As Intended, which means this is not considered a bug and will not be fixed. Please do not leave a comment on the linked ticket.

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