Actually, someone else said Apple admitted to it being their problem - and since it's clearly present in a wide range of games ranging from demanding titles like Genshin, Wild Rift and PUBG to side scrollers and old games like Clash of Clans, I'm very much inclined to believe it's an Apple issue. It applies to all games, only exists in iOS and iPadOS 16+ and miraculously disappears if OS is downgraded to 15.7 or earlier.
Workarounds like that should not be a normal and accepted thing for new supposedly premium devices but I'd happily take the option, except Apple doesn't actually allow that for newest devices like iPhones and M2 iPad Pros so many of us are stuck with this infuriatingly laggy mess instead.
Also, fwiw - you mentioned you play on high settings with super high resolution, but this issue has nothing to do with that; it isn't game-related lag due to throttling or resource hogging. It's the display management system interfering with in-game settings. I even posted some further links to Unity devs discussing this issue on another thread.
The reason this worked is because turning on screen recording switches off ProMotion and forces a constant 120 FPS frame rate onto the device. Ergo, further evidence the issue is caused by ProMotion.
This is not a solution though, because many games that otherwise run smoothly will eventually throttle with the added strain of screen recording (not to mention the massive files which would result from this if playing for long enough).
Nothing to do with silicone. I have 2 M2 iPads and several M1s - none of the M1s running OS 15 show it, and one of the two M2s has a sustained performance score almost 10% higher than comparable tests done through WildLife in reviews and YouTube. It's a simple matter of ProMotion being buggy, the chips are more than capable to run games like these smoothly if Apple could fix their $&%^# screen software.