Apple's "retina displays" aren't mapped to any specific PPI number. It depends on typical viewing distance for the device it's on (e.g. an iPhone would need a higher PPI to be "retina" than an iMac which would sit further from your face)
So for a device like this you'd probably compare it to an iPad. The latest one is 264 according to a quick Google search.
That's not to say this thing's display is bad by any means, but it's worth noting.
Valve's new Steam Deck 7" @ 215ppi has essentially the same pixels per inch as the new Nintendo Switch OLED 7" @ 221ppi, so from a gaming perspective their target aligns with their direct competitor's hardware. You're right that an iPad has a higher PPI, but Apple typically runs a lot higher on PPI compared on all platforms (handheld and otherwise), and in this case, now that I've run all the numbers, I think the Switch would have been a better first point of comparison for a successful gaming deck handheld than the iPad. (I just happen to know Apple's macOS retina PPI by heart, is all!)
I do recommend measuring the distance from your eyes to a gaming handheld that you're playing while it rests in your lap, and then measure the distance from your eyes to your work monitor; for me, these are only a couple inches different, so it makes sense to me that Nintendo is willing to let the PPI drop down to Apple macOS Retina levels with this year's OLED update, since they have some PPI room to work with.
Detailed breakdown for the curious:
Apple's macOS retina displays are all 220ppi +/- an insignificant amount:
MacBook M1 Air 13": 227ppi
MacBook Pro 13": 227ppi
MacBook Pro 15": 220ppi
MacBook Pro 16": 226ppi
iMac 4K Retina 21.5": 219ppi
iMac M1 24": 218ppi
iMac 5K Retina 27": 217ppi
Apple's iPadOS retina displays are all 264ppi, except the 8" Mini which is halfway to an iPhone (probably to maintain fidelity at the much lower screen size?):
iPad 7.9" Mini: 326ppi
iPad 10.2" Retina: 264ppi
iPad Pro 11": 264ppi
iPad Pro 12.9": 264ppi
Apple's iOS retina displays are all 460ppi, with negligible variation, with the Mini offering more support for the "maintain fidelity at small sizes" thought above:
iPhone 12 Mini 5.4": 476ppi
iPhone 12 6.1": 460ppi
iPhone 12 Pro 6.1": 460ppi
iPhone 12 Pro Max 6.7": 458ppi
However, the nearest competitor to this Steam device is actually the Switch, so let's look at that. These numbers might be off by a few points, but essentially Nintendo seems to maintain the exact same resolution and just sizes the pixels based on that:
Nintendo Wii U 6.2": 158ppi
Nintendo Switch 5.5" (Lite): 267ppi
Nintendo Switch 6.2": 237ppi
Nintendo Switch 7" (OLED): 221ppi
And finally, Valve's entry here is nearly an exact match for the 2021 OLED Switch:
