I honestly picked up a mini PC for this exact purpose. I grabbed and gutted a Unico cabinet while it was on sale. (I don't recommend them for anything other than the metal shell). I literally replaced the monitor, the amp, the speakers and some of the harness and the fans. I kept the encoder boards and the PSU they had built into it. I bought this when it was on sale and before things had gotten stupid in the PC landscape due to AI. https://a.co/d/09ARm0nI Then I opened up the side of it and used a NVME to SFF8612 adaptor to feed an RX 9070 XT into it from an eGPU dock. Again, I caught some deals before everything had exploded in price. All of this combined with a pretty simple power script gave me the arcade experience I was looking for. It runs a script to bypass visible windows booting, launches steam directly into big picture mode which plays very nicely with the encoder boards and had a direct system shut down from the menu within Steam big picture mode. I play everything from classics like Pac-Man, to later generation titles: Marvel Vs Capcom 2, Capcom Vs SNK 2, Street Fighter 3, Soul Calibur 6 to current generation titles: SF 6, Tekken 8, TMNT: Shredders Revenge. I've had zero problems with this set up once I got everything situated and figured out.
The GMKtec EVO-X2 is much smaller than the steam machine while costing more. If size was really the most important factor, that would be a better choice. Built for AI, but can game quite well when the competition is the hardware inside the Steam Machine. We all know size isn't as important as people say though so they could go for something like the TOPGRO T1 Pro for nearly the same price but for a much better machine that is slightly taller but thinner than the Steam Machine. It's around 5L instead of 4L but with better specs. There are absolutely alternatives out there that make sense for people who aren't dead set on buying the Steam Machine simply because it's made by Valve. https://www.amazon.com/TOPGRO-i9-13900HK-Computer-Adjustable-High-Performance/dp/B0D8BBF849?s=electronics&th=1 https://www.gmktec.com/products/amd-ryzen%E2%84%A2-ai-max-395-evo-x2-ai-mini-pc?variant=46826048323738
