We have really interesting and good hardware, but it is all moot because the software landscape is plain hell. I really puts me off to ever use a Apple or Google platform.
I would immediately jump to x86 regardless of power consumption. Would probably still run better than my current phone with a sizeable battery because 95% of CPU time is crappy routine you didn't even want running, so that is a software problem as well.
With the power usage of screens, I doubt an x86 processor would be noticeably worse.
Sorry for the rant, but I don't understand how anyone could react differently if they hear the word Android or iOS. Why did we end up with this crap?
Software is what people want and once a software ecosystem settles in place it gets a lot harder to move away later because of all the stuff you have to adapt and fix.
As far as I can tell there's no inherent reason an x86 device would have worse battery than ARM if you use the right processor. Pick up some small Lunar Lake chip, tune it low, aggressively tune the tasks you allow to run in the background etc.
Cellular is a bit annoying, and I can't speak at all to the difficulty of integrating with legacy phone services, but data access seems pretty easy to get with an external modem (maybe power consumption will suck..)
Definitely phone software landscape is abysmal. Everyone trying to lock down their stores and charge egregious prices to developers for the privilege of giving them access to their captive user markets. Makes me appreciate how fortunate we are to have Linux at all, and even Windows is leagues better, although MS is doing everything they can to develop their own little walled garden, albeit thankfully that horse has long bolted.