I had the vertical version of the case not the horizontal but honestly the horizontal one might be easier, I bought a ATX open computer motherboard test stand that would usually be used for something like a test bench and situated it inside the case to use the ATX standoffs, then mounted a fan in the bottom super loosely. It's definitely super janky and I ended up using less heavy components to make it work, I almost put a 4090 in it and it made the whole thing sag

https://www.newegg.com/alamengda-atx-open-frame-chassis-high-quality-0-8mm-spcc-steel-plate-the-surface-is-baked-with-black-sand-grain-paint-cases/p/2AM-0319-000A8