Not sure if it opens up that much on them as far as their security processors go. Modern consoles already treat DRAM as completely untrusted (an attacker could just sit on the DRAM bus and sniff/issue requests there).
The Xbox One for example encrypts all the DRAM it uses after it gets out of the main CPU die. See this part of Tony Chen's presentation https://youtu.be/U7VwtOrwceo?t=956
Also see this bit on the Apple Secure Enclave in the "Memory Protection Engine" section which also explains how they encrypt stuff stored in DRAM: https://support.apple.com/guide/security/the-secure-enclave-...
wouldn't request after DRAM controller be unencrypted ? Would need to have different key per memory type and even then you could do some damage as realistically it won't have number of keys equal to running processes