You can get pretty sleek mini-pc in the price but, there performance is sub-par compared to the price they are asking for.
While itx for factor is very expensive, m-atx is cheaper and there are quite few sleek cases for them.
If you are looking for prebuilt mini pc, asustor flashtor is pretty sleek if you only want m.2 storage.
The point about GPU's is pretty dumb, you can rent a stack of A100 pretty cheaply for a few hours. I have done it a few times now, on runpod it's 0.79 USD per HR per A100.
On the other hand the freely available models are really great and there hasn't been a need for the closed source ones for me personally.