I'd suggest maybe stick with Godot 3 until 4.1 comes out. I just started playing with 4, and hit a bug where Godot will hard crash whenever you try to view the Terrains tab if you've created terrain sets, used them in your scene, then deleted the terrain sets.

Also, Godot 4 doesn't have as good support for older systems due to the new Vulkan backend. I worked around this by switching to the mobile renderer which works better on my old hardware.