I don't understand what Rust has to do with the chip circuitry, beyond stuff that could be compiled to RISC-V code to run on the emulator. But it seems to have more stuff involved.
Also, I don't understand what about AES can be taking up so many LUTs.
The Rust business appears to be stuff to generate compile-time constants identifying addresses of peripheral registers for (Rust) code written to run on the core. Apparently the addresses change as you add and remove various peripheral gadgets.
It is doing AES rounds sequentially. It might be that real-time generation of round keys uses up a lot of LUTs.
Also, I don't understand what about AES can be taking up so many LUTs.
Clue, please?