In general when I install Linux on an Apple device I just assume there isn’t the same level of performance. I remember installing mint on a 2016 intel MBpro and the limitations/cons didn’t surprise me at all because I just kind of expected it to perform at 70% of what I expected from macOS but with far more free freedom/control. It ran very smoothly but you definitely lose a lot of functionality.
That's very cute, but it's not why Apple laptops run Linux poorly.
Apple Silicon has terrible and inefficient support because Apple released no documentation of their hardware. The driver efforts are all reverse-engineered and likely crippled by Apple's hidden trade secrets. This is why even Qualcomm chips run Linux better than Apple Silicon; they release documentation. Apple refuses, because then they can smugly pride themselves on "integration" and other plainly false catchisms.
And on Intel/AMD, Apple was well known for up-tuning their ACPI tables to prevent thermal throttling before the junction temp. This was an absolutely terrible decision on Apple's behalf, and led to other OSes misbehaving alongside constant overheating on macOS - my Intel Macs were regularly idling ~10-20c hotter than my other Intel machines.
I have no doubt you have good information after this, but this sentence makes me not want to read any further.
And yes, your statement was a cutesy catechism with no actual evidence provided. A big reason why Apple tech doesn't work like a normal computer is Apple's rejection of standards that put hardware and software in-concert. ACPI is one such technology, per my last comment.
iBoot2 loads the custom kernel, which is a build of m1n1
So can Apple stop signing new iBoot2 versions? Sure! And that sucks. But it's a bit of FUD to claim that Apple at arbitrary points in time is going to brick your laptop with no option for you to prevent that.
Granted, if you boot both macOS and Asahi, then yes, you are in this predicament, but again, that is a choice. You can never connect macOS or recovery to the internet, or never boot them.
In other words, you're completely fucked if you brick your install. I consider iBoot a direct user-hostile downgrade from UEFI for this reason.
YMMV, but I would never trust my day-to-day on an iBoot machine. UEFI has no such limitations, and Apple is well-known for making controversial choices in OTA updates that users have no alternative to.
That's a bit of a creative perspective, isn't it? You have no control over the UEFI implementation of your vendor, same can be said for AGESA and ME, as well as any FSP/BSP/BUP packages, BROM signatures or eFused CPUs. And on top of that, you'll have preloaded certificates (usually from Microsoft) that will expire at some point, and when they do and the vendor doesn't replace them, the machine might never boot again (in a UEFI configuration where SecureBoot cannot be disabled as was the case in this Fujitsu - that took a firmware upgrade that the vendor had to supply, which is the exception rather than the rule). For DIY builds this tends to be better, Framework also makes this a tad more reliable.
If anything, most OEM UEFI implementations come with a (x509) timer that when expires, bricks your machine. iBoot2 is just a bunch of files (including the signed boot policy) you can copy and keep around, forever, no lifetimer.
Now, if we wanted to escape all this, your only option is to either get really old hardware, or get non-x86 hardware that isn't Apple M-series or IBM. That means you're pretty much stuck with low-end ARM and lower-end RISC-V, unless you accept AGESA or Intel ME at which point coreboot becomes viable.
[0](through any user-accessible software action, obviously)