Intel Macs aren't relevant anymore. As for apple silicon, running a ubuntu VM doesn't count. You also need to use Parallels, which is not free. The Asahi Linux method is still very buggy because its essentially a reverse engineer of Apple. And its not guaranteed to ever not be buggy, because Apple. And Apple will 100% kill it if it ever gets to popular because it runs well, because they will lose revenue streams they get with MacOS.
So the definitive answer is no, Macs are still pretty much locked down.
I get that people like the battery life and the hardware of Macs, which is fine for personal use, but objectively for a laptop that is going to be used for development, you get much more utility out of buying a "non mac" laptop of your choice in the form factor, and installing Linux on it.
In what way, today, has Apple prevented you from running whatever you want on a MacBook? Not some hypothetical "And Apple will 100% kill it if it ever gets to[sic] popular" future action by Apple, but an actual thing they've done to stop AsahiLinux, or someone else, from making the progress they've been making, on trying to run on bare metal?
In macOS, I am not prevented from running whatever I want. There are some extra buttons to click to allow certain kinds of software to run, but ultimately, Apple doesn't have a say on what I can and cannot run on my Mac. Macs aren't "still pretty much locked down" because the open source community hasn't been able to make a kernel up to your standards. That's just not a commonly accepted definition of "locked down".
If it ever get to the state that modern linux is, then I will change my mind. Its very much like the linux of 2010s, where you had to configure a whole bunch of things to get linux to work despite people swearing that it works.
