My system version instead runs on RISC-V, so no custom FPGA implementation, currently on an emulator, but eventually on the ESP32 (which has a much better availability).
Well, the MiSTer project was yet 4 years from being launched back in 2013 when the RISC-5 was implemented in FPGA, so I hope you'd excuse Wirth from not choosing it.
FPGAs were never that maker friendly, due to the whole ecosystem.