No puedo desbloquear el desafío número 4

[LtheDoc]

Se supone que ya hice lo necesario para desbloquearlo, pero hasta ahora nada

[Nazemec]

Disable all mods and make sure the debug console is disabled as well.
Check here how to enable the debug console, just put it at 0 instead of 1 to disable it:
https://bindingofisaacrebirth.fandom.com/wiki/Debug_Console
You can enable them again and still unlock things once you've unlocked the Womb (first Mom kill, in-game secret number 4). Before that point, they prevent all progress. This isn't a bug.

List of things that prevent all kind of progress:
- Seeds (except a few special ones)
- Challenges (except for their reward obviously).
- Daily Runs.
- Reruns and Victory Laps (except for a few specific unlocks).
- Any active mod from the mod menu before Mom is killed once on that save (no matter what they do, other saves are irrelevant).
- Enabling the console before Mom is killed once on that save (even if you don't use it).
- Paranoid antivirus programs (or missing rights) preventing the game from creating/editing its save file.