What device are you coming from? Do you actually need to upgrade?
Most people don't experience eye strain/headaches. It's a real problem, but it only affects a relatively small percentage of the population: people sensitive to the display's PWM implementation. If you're not one of those individuals, then X/XS should be a viable choice.
Re: reception issues - again, seems like most people don't experience those problems. That said, I wouldn't be surprised to see Apple release some sort of update addressing these concerns. As mentioned above, you might want to wait to see what Apple does here.
Every phone has some kind of problem(s). I'm sure the XI (or whatever it will be called) won't be exempt. Eventually you'll just have to make a choice, and live with whatever shortcomings the device has.