Weeks?
Months, minimum. Maybe years. The path to being a game dev isn't short or easy, but it is rewarding.
One day I'll understand that, but it is too much for me at the moment.
It'll be too much for you until you take up the challenge and conquer it. The way you grow is by taking on difficult tasks.
I do really like the idea of a minecraft clone.
Me too. While you could use something like Godot for rendering, you're going to have to write the entire voxel system and inventory system from scratch, and that's the hard part. You'll also most likely have to write a bunch of custom shaders, mesh processing, and texturing code in order to efficiently render the voxels due to the great number of textures and the weird baked-in lighting.
And, I don't like minetest, it is super resource intensive for some reason.
Lua and an ancient graphics engine (Irrlicht).
Java vs C++
Minetest leans heavily on Lua. While luajit isn't the slowest thing out there, it's slower than Java. More importantly, the interface to the C++ is awkward and inefficient, and the semantics of Lua preclude writing efficient code (ie, tables instead of structs).
And, I still want to make a minecraft clone.
Do it. Use allegro for the boilerplate, per @icedquinn