I've used Steam Link to play games from my Steam library on the Apple TV using a video game controller and it worked surprisingly well. You still might want the Playstation (or Switch or XBox). Just depends on what games you want to play.
I found the input latency to be much worse than the PC connected to the same TV, for whatever reason.
I thought I surely was imagining it, so I revisited it 6 months or a year later, and, yes, the input latency from the controller is substantially worse on the Apple TV.
Moonlight works really well on the ATV4K too. I stream 4K@60FPS with HDR and surround sound from my PC using the Apollo fork of Sunshine (creates a virtual display since I normally game at 1440p on my attached monitor).