There's literally a GUI toggle that Apple provides to disable boot security and allow you to boot anything you want... AS has had the ability to run third party OSes without, say, iPhone style jailbreaking since the beginning. They arent actively *helping* get Linux running, but they arent actively stopping it either the way they do on, say, an iPhone, and they're unlikely to start.It does seem increasingly more likely that Apple will only support direct booting of macOS on Apple Silicon Macs and that any effort to natively boot any other OS will have to come from the kind of reverse engineering that the Asahi Linux project is working on.
I'd also bet we'll get bootcamp for Windows 11 on ARM as soon as Microsoft's ARM exclusivity deal with Qualcomm expires, though when that happens is being kept pretty hush hush by both companies. AFAICT the blocker on that isnt Apple, it's MS/QC