Just tried baking in Blender 3.2 and I think it's important to note that in the Object Data Properties under "Color Attributes"Color Attributes the vertex color setup should look like this:
I had to create a new color attribute using the "+"+
button, because the default one was set to "face corner"Face Corner* and "byte color"Byte Color which gave me a completely black bake.
Might be a no-brainer for some, but I thought I would add it here.