At least in Valorant, DMA is becoming impossible due to IOMMU / Memory Integrity enforcement. The only option is becoming pixel bots.

As for faking the input device: I'm sure it's possible, but I'm also sure that perfectly spoofing an input device is much easier said than done.

Even if it is possible, all they have to do is make it hard enough to where the percentage of players cheating is at the point where you will rarely if ever encounter a cheater in your matches. As far as I'm aware, Valorant is one of the only games that has accomplished that.