The most generic way to disable a node entirely is to remove it from the tree temporarily, and store it somewhere so that you can put it back later. I'm just not sure if signals will turn off, maybe they remain.
Another way is to delete it entirely, and re-instance later.
Other more efficient solutions will switch only the relevant states, so it depends on the node and scripts it might have. You could want to:
- Hide it
- Turn off its physics shapes and layers so it no longer collides
- Stop any sound it might play
- Disconnect its signals, or add checks in its script
That means the concept of "disabled" is highly specialized to what you actually want, so quite often you need to write that yourself.