Rpi is not always such a gold standard either.. is their boot chain still a mess? That was one of the problems with zero 2w
All of the boot chain is a mess because the Pi 1 used a bucket load of unused Broadcom set-top-box SoCs which were GPUs with a tiny ARM core along for the ride. Every Pi boots off the GPU first.
TBF, booting any Arm board is a mess. Rpi gets my kudos for frequently updating kernel sources, unlike any other SBC I have tracked. I know which gauntlet I'd rather run to enable secure boot on an Arm SBC., despite the weird architecture.