kohlrak: Careful what you wish for. OLED phones are experiencing some severe screen burn, right now. Particularly on interface parts that don't move (so health bars and things like that for this device).
I'm an OLED user for about a decade now, pretty much went from crt to plasma to oled, resorting to calculator displays only for office and casual stuff. First thing I did with the tv was to discard the factory settings and tune/calibrate it (esp. brightness) for dimly lit room. It is used primarily for movies and some gaming too. Some decluttering of HUD in games is a way to go with it to minimize risk of burn-in, which suits me as I dislike visual overload in games that go for mmo-style huds, with pointers, minimap, numbers flying everywhere nonsense. Btw I run it around 10% brightness as a sweet spot. I thought that me saying "If only papaGaben would offer an OLED model for those who don't play while out in the sun much" gave it away that I would run it at low brightness to prevent burn-in and fade of blue colours. Also screensavers were a thing since crt days for a reason. Btw this is just the very reason why I wouldn't consider a second hand oled ps vita unless I knew the person who had it and how they ran it. I know precisely what I wish for here, but I understand you meant it all well for a general user.
kohlrak: The thing i like about APUs is their increased bandwidth between GPU and CPU. That is something severely underestimated, and i suspect this is what is behind games like Horizon: Zero Dawn running horridly on some computers despite running so well on others (including the PS4).
As for clock speed, either i'm misinterpreting what you're saying or it's a non-issue: the clockspeed and the voltage are not necessarily linked. To the contrary, a lower voltage means you can clock it higher since it won't generate as much heat, though you may need to keep a CPU lower for reasons other than heat (result stablization of individual instructions).
Interconnect between cpu and igpu is a nice thing for the low latency, however in reality it doesn't do such magical things as you might expect, esp. if you consider that they both share the same memory, its bandwidth and possibly the memory controller too which causes the latency bottleneck. Though with steamdeck I'm less worried since they at least use ddr5. Makes one think how it would perform with something like stack of hbm2, but the price would skyrocket.
APU as design is a compromise by choice, cpu portion of apus in general has a lower cache compared to desktop-only architecture, igpu part having fewer CUs and to top it off, they share the tdp envelope as I already said. There is only so much you can do with those 15W to play with. For mobile usage it's good enough, esp. the size and efficiency is great with lower clocks.
Console ports sometimes running like crap won't be solved with the low latency interconnect that apus have though (believe me, I tried with my APUs - heck my old kaveri apu doesn't even have L3 cache on cpu side, which hurts its performance). It all boils down to optimizations of a native version for 1 console vs a myriad of hw/sw setups and porting to them.
As for clockspeeds of apu in general, with mobile tdp and the cooling solution used, you likely won't reach max advertised clocks on cpu and igpu at the same time, because when the tdp gets reached, it will throttle one or the other or both down. Undervolting and over- or under- clocking as a practice was just my experience with amd products, since their gpus were notorious for coming overvolted out of the factory, where you could easily undervolt them and get much better thermals without any loss of performance. If you underclocked to boot, you would get insanely low power consumption, esp. on gpus with hbm of any kind. Sorry for confusion, didn't imply that voltage and clockspeeds were rigidly linked or whatever.
As for this device, I wouldn't preorder it until I see tech-heavy reviews, how it performs, what options it offers to prosumers, etc and then again I'm not much interested in handheld without oled display (or microled in a decade from now).