This doesn’t really give you any direct suggestions, but I run MacOS 9.2.2 unsupported on mine, with VirtualPC 6 running Windows 2000, and use it for arcade game development. I built an arcade cabinet running an old Pentium 4 Dell, and network the Mini with it to test changes. I use an old development suite called Multimedia Fusion 2 that doesn’t require any code writing, and get to live my 80s dream of creating arcade games 😁