As a Linux, macOS and Windows user it’s really strange to me that you can’t just install the latest OS on your device. Even my iPhone updates to the latest version as soon as it’s released.
Besides, the phone software is highly optimised for the specific hardware. It is not a generic software like Windows
Seriously, why can't Android just be installed? Are they building it like the old-timey kernel before modules and embedding drivers in a giant monolith or something ridiculous?
But there's also nothing to stop you simply building the latest kernel from source and using that - it's pretty easy and it will work fine.
Yes, it does (CachyOS).