My PC is a desktop. And yes, it's getting way too old...
Would looking at godot's code give any hints at what might be the issue? Probably a long shot, but then I don't know what line 4882 in rasterizer_scene_gles3.cpp is about (this is the stdout error I get, that I posted before):
OpenGL ES 3.0 Renderer: ATI Radeon HD 4800 Series
ERROR: RasterizerSceneGLES3::initialize: Condition ' status != 0x8CD5 ' is true.
Continuing..:
At: drivers\gles3\rasterizer_scene_gles3.cpp:4882
EDIT: I just noticed, I also get this one:
ERROR: RasterizerSceneGLES3::initialize: Directional shadow framebuffer status invalid
At: drivers\gles3\rasterizer_scene_gles3.cpp:4907
The behavior is confusing though. It doesn't seem to me like it's logically related to this (though it may be, I'm just saying). It gives me these errors during initialization, but doesn't give any errors when it hangs. And it hangs in a specific pattern: it hangs for ~10secs the first time I select or create a Spacial, and then I can use all the Spacials in the world without hanging. It will hang when I select some other type of node, say, a RigidBody. And after that I can use RigidBodies without hassle. It does the same for every other node that makes it hang (many or most 3D nodes). It's only the first time for each node. (though it also hangs when running a game, and gives me those errors in godot's error reporter)