DMA cheating and is there anything being done?.

Modern consoles can't be hacked that way. Their operating system and all content on the device is cryptographically controlled using cryptography that has not been compromised.  You cannot install any unapproved software onto them in order to gain necessary hardware/software access to cheat per the subject of this thread.

Please describe what cheats the person you claim were using.

The only available console cheats are hardware-based add-ons. One common type is the devices that adjust the controller inputs to reduce recoil, run macros to make you harder to track, or slightly exploit aim assist. They are pretty benign in the grand scheme of things and are only really powerful for a person who is already skilled. Don't get me wrong: they are cheating, but not to the extent possible per the subject of this thread. The other type is EXTREMELY uncommon and requires a camera or video capture device to record your tv/screen, software running on a computer to interpret that data, and a device plugged inline with your controller to inject movements into the stream of input data. That method is very expensive, time consuming, requires a device which is no longer being manufactured or supported by its manufacturer, and AI training that can take many months to dial in. A very small percentage will take on that pursuit. And even then, wall hacking is impossible and you are still limited to reacting to what is seen on the screen and hoping that the lighting is good enough for a person to be seen.

The majority of powerful cheats are on PC because of the ease to implement and the low cost.

I am curious what console cheating you saw; especially in relation to the subject of this thread.