Yes, UEFI is messy, not saying you will never have issues. But on the other hand, in OpenWRT you literally need to build an image for each device, something that you (almost) never have to do with UEFI or BIOS. Or when was the last time you had to build a specific image for a x86_64 laptop? If this happened to you, I am curious, this would probably make a nice blog post.

By the way, I am not saying that UEFI is not complicated, but there is probably a middle ground between "we need to build a specific image for this device because its bootloader is dumb" and "we have a f* operational system as a bootloader that works everywhere but is full of holes".