Yeah pretty much. I don't disagree on principal that people should be able to install a custom OS on their device. But in practical terms it doesn't really matter all that much because hardware is so complex and moves so fast that no hobbyist has even close to the time and resources to develop a custom OS for the latest phones.

The M1 Macbook Air is 5 years old now, has an active development, lots of community funding and attention, yet is still missing basic functionality like external monitors and video decoding. Because it's just a mammoth task to support modern hardware. Unless you have a whole paid team on it you've got no hope.