I just bought a Beelink SER9 mini pc, about the same size as the Mac Mini. It's got the ridiculously named AMD Ryzen AI 9 HX 370 processor, a laptop CPU that is decently fast for an X64 chip (2634/12927 Geekbench 6 scores) but isn't really competition for the M4. The GPU isn't up to desktop performance levels either but it does have a USB4 port capable of running eGPUs.