Yeah I see the Commander X16 as a bit of a folly, a hobby project by some serious retro computer nerds. I don’t think it has any viability as a platform, even as a gaming platform, as it’s a strange implementation of a weird architecture.

That said, yeah there really isn’t something that is as imminently accessible as a C64 was, where the machine itself plugs into a monitor and keyboard, and you program the device using itself.

Arduino requires a PC or other device to compile and run code, most of them are very low power devices that must have compiled binaries, so they’re programmed in C++.

Maximite is another guy’s attempt to have a standalone BASIC machine. Uses fairly modern hardware but it’s still some guy’s project, and runs BASIC rather than anything remotely modern.

Raspberry Pi and other Linux SBCs are surprisingly powerful, but also very complicated to run. You can do a college degree in Linux sysadmin.

Meanwhile, I’ve played with the MicroPython language a bit, and as cool as it is, it can be a pain in the ass to manage because it runs on a microcontroller meant to be programmed from a PC, so there’s a pile (not a stack, not a heap, a pile) of software you have to manage. So it’s cool, but sorta supported on a bunch of platforms none of which are amazing to use and it’s got almost every problem that Arduino does.