Load maps when the game is compiled and running

[TomMars]

It is possible to open a .map file when you compiled your game and you running it?
I want to let users create custom maps like in Source's games.

[Shfty]

Yes, Qodot can load map files at runtime:
Qodot Wiki - Usage / Using Qodot at runtime

There are some limitations around custom resources to be aware of - since things like textures (both loose and WAD-based), models and materials need an editor-side import process before they can be used, maps loaded at runtime can only use resources that already exist inside your built project.