Yup, Amazon supports the 6.11? kernel on aarch64. Most toolchains if you target linux aarch64 static they, they will produce executables that will run on Amazon Linux aarch64 and Android, set-top boxes with 64-bit chips and Linux 3+ it's surprising how many devices a static aarch64 ELF will run on.

As far as I'm aware- if it's called an ARM CPU it's either the v7 or v8 instruction set with the possibility of extra instructions (changes to ARM die) or a tightly integrated coprocessor (via AXI bus, adjacent to the ARM silicon on the same substrate).

There are different Coretex series that optimize for different things- A and X for applications (phones, cloud compute, SBCs, desktops and laptops), M for microcontrollers, and R for realtime.

This doesn't apply if the company has an ARM founder and/or architecture license. (I think that's what they're called) Eg- Apple and their M series SOCs are not Coretex cores, but share the base instruction set- but only if Apple wants it to.

Yes, think AMD vs Intel. Same x86 target but built differently under the hood with potential to optimize for certain uses over others.