I came to this because I was involved in a very very minor way with FreeGEM and the project to resurrect PC GEM after Caldera made it GPL.
There was the idea to somehow port TOS to x86, but as we discussed it, the issues became clear. A native ST os on x86 couldn't run ST apps, because they're 680x0 code. And it won't run PC apps either, as they target PC OSes, not TOS/GEM.
Even if it's doable, it's a vast amount of work and there's no point. You still need emulation.
This is also why Apple ended up buying NeXT and switching OSes. Remember, Apple already had a UNIX: it had A/UX. But A/UX is a native 68030 Unix, with integrated classic MacOS. If Apple ported the underlying Unix to PowerPC, the embedded MacOS part that provided the UI wouldn't work, and MacOS apps wouldn't work. Without that, there's no point.
So Apple built a 68k emulator and ported the OS to the emulator. Then it speed-tweaked some bits. It worked and it delivered fast RISC Macs for a decade or more, which could still run old 680x0 Mac apps, but also allowed for new PowerPC apps to be delivered.
It was a good strategy, but it left them in a dead end. Copland failed, and so that's why NeXT, which was an excellent deal.
Well, honestly, we're not going to see any major new ST/TOS apps in 202x. It is not going to happen.
But there is this rather neat all-FOSS OS, or even pair of OSes: EmuTOS and FreeMINT. And they have apps, and programming languages, and are still vaguely usable.
So my thinking was: is there any way to glue together some existing code that enables them to run, providing an emulated 680x0 environment, on this cheap readily-available ARM hardware, without there being a whole other OS underneath?