Conclusion after digging through all three: if you already own a working MiSTer, there's no compelling reason to chase the newer ARM boards for "better" performance, the practical difference is marginal, and MiSTer's broader core library wins in the long run.
+ +For now I'm not running original hardware, I reproduce my Amiga on the MiSTer FPGA using the Minimig core. My classic Amiga is mapped out there with Workbench and the tools I used back in the day, spread across different configurations and several Workbench versions, so I can revisit exactly how the machine felt across the years.
+I'm still keen on the real thing, though. Retro Games Ltd. is working on an Amiga 1200 console, and I've been following everything public about it. There's a dedicated page on that: The A1200: What We Know Before It Ships.