crosscompiling chain?

[ryo]

While I understand and agree that's it's technically possible to compile directly on the phone, from a horsepower, time, storage space, and heat perspective, I would imagine that's neither the preferred nor recommended way of approaching things.

Like I said, this only makes sense for consumer toys, not for PCs.

Are you suggesting that developers are not building to one of the the aarch64-* targets in GCC on a normal desktop, with the requisite libraries installed?

yup.
You can however compile on your own PC and test on it.
Then compile on your phone as is.
You can't just compile x86 or x64 apps, and expect them to work on an ARM64 processor.
Same for the other way around.

While, again, I admit that building directly on the phone is technically within the realm of possibility, I find that rather unlikely.

Spoiler arert: I have a Pinephone, and I develop software.