Leviatán

On a Windows 10 machine, after opening the door, there's still a collider in front of it keeping me from entering and it doesn't load a new scene either.

Also, a tip regarding the camera:

You can keep the camera from going inside rocks if you shoot a ray from the player backwards and put the camera at the hit point if it's closer than the preferred distance. I'm not sure how to do that in Godot, but here's the logic:

var maxDistance = 5 // this holds the value of the preferred camera distance. Feel free to change it
var camDirection = Vector3(0, 0, -1) // These are local coordinates and can be changed to preferred direction
// In this example 'Raycast' returns the hit's position or null if it hit nothing. However, I don't know how it works in Godot so you should look up the syntax.
var hitPoint = Raycast(/*from*/playerPosition, /*towards*/(playerTransformBase * camDirection)
if(hitPoint != null && length(hitPoint - playerPosition) < maxDistance) // If the distance(length of difference vector) between hitPoint and playerPosition is less than maxDistance, that means the camera would be inside the rock and we need to adjust it
    camPosition = hitPoint // Here I simply say we put the camera to where the raycast hit the object
else // otherwise 'hitPoint' would be too far, so we put the camera in the air in camDirection at maxDistance
    camPosition = playerPosition + camDirection * maxDistance // I'm assuming 'camPosition' is the absolute position of the camera and not the local position

This might seem complicated, but once you get the hang of it, it's actually pretty simple. Still, feel free to ask if you didn't understand something, but I can't promise I'll reply right away.

Cheers,
Alexa