Just add a monitor and a controller.
Apple markets its newest iPhone 15 as a powerful device that can run popular games with no issue, and it might actually be true. Moreover, you can even replace a console with the phone as content creator Vincent Zhong demonstrated in a recent video.
He connected an iPhone 15 Pro and an external monitor with a USB-C, Apple's latest addition that might have something to do with the EU's requests, and used a controller to emulate a gaming console in a way.
Zhong then played Resident Evil Village for a while, and it does look good, although I wouldn't seriously compare it to PlayStation or Xbox. Still, it is impressive for a multifunctional device.
Image credit: Vincent Zhong
The first thought you probably had when you saw the footage was, "This thing must be hot as hell." While I can't confirm or deny this myself, unfortunately, several days ago YouTube channel Geek Culture ran Resident Evil Village, Genshin Impact, PUBG: Mobile, and Honkai: Star Rail on an iPhone 15 Pro Max, and the temperature didn't rise too much. Geek Culture said the phone stayed comfortable to hold after about 30 minutes of playing, so maybe iPhone 15 is a viable option for gaming.
Plus, if your phone gets too hot, you could always buy a cooler, although it doesn't sound like something many users would do.