Close to 2 million faces, high levels of subdivision surface modifiers, large textures 2K and 4k... all of that uses resources from your computer and eventually you will run out of them.
Why does Blender use so much memory for large textures?
Using 4k textures on something that will only be a few hundred pixels tall on the screen is wasteful.
If you need any to make any mesh in blender look "minecraft-like", use a Remesh Modifier set to Blocks. You can then export this to a variety of formats, including .obj. If you need a .vox file, however, you will need a special addon. One of the best I can find to suit your purpose is here, but I can not vouch for its efficacy.
Addon to export to ....
I found that my selection of the baking options was the problem.
Initially I unticked everything except "Ambient Occlusion" (following a few online videos) - this left the primary baking type to "Combined", with direct and indirect light and Ambient Occlusion ticked.
I bounced around online for a while before going in to look ...