Brume is using the Marvell Armada 88F3720, which uses the ARM Cortex-A53 processor. This architecture supports the ARM8 cryptography optimisations including AES:
Whether it’s utilised in the binaries I have no clue. But the BRUME is one of the best performing GL-iNet products for VPN, but particularly for WireGuard which does not use AES (instead it uses CHACHA20).