The optimum AoA for approach, climb, range etc. is what it is. The speed is a result of your configuration at the AoA ( slotted flaps, leading edge devices, etc factored in).
The jet stalls at "x" AoA, and speed could be above or below the manual's number - think accelerated stall and such.
Gums, you've lost me. For any configuration, there is only one speed that will give you a particular AoA. That is why Vref to the knot is used by airliners. Somebody decided many moons ago that speed would be a better "target" to use.
Airliners generally don't do accelerated stalls
so the stalling speed is always the same for a particular configuration and in any case is calculated by the FMS (taking into account all sorts of things like C of G) and is displayed on the ASI by way of Vref, being the stall plus 30%.
We usually set a power of 95% or so for our wingies when climbing. Then we climbed at a mach or a generic speed while trimming for such. Sheesh. Easy. Upon level, got to the best mach and used whatever power we had to, duhhhh? Why is that so hard?
Who said it was hard? What you've described is exactly what happens in a jet airliner; climb at constant power using pitch to control the speed, then in the cruise, use power to stay on speed.
For approach, if you need otto to help, then fine. but quit connecting the throttle to the AP modes. If you want to "point" and use throttle for speed, your choice.
?? As has been pointed out already, having the autothrottle control the speed reduces workload. The autothrottle can be used with or without the AP being engaged. It is not "connected" to the AP modes. It does different things depending on what the AP is doing with the aircraft but that is generally reactionary eg AP pulls nose up to get back on GS, autothrottle pushes up power to keep speed on target.
Some types, like mine, recommend using the autothrottle all the time, AP in or out. And it does a far better job than I ever could. "pointing and using the throttle for speed" is simply flying without the AP or the autothrottle. Problem?