Bunch of whiners...l
Dual A/P GA, both A/P and A/T remain engaged. Thrust commanded to reduced thrust ~88N1 if single press, full G/A thrust with second push. LNAV will engage for the MAP if armed. Catch: Dual A/P only available for ILS.
Single A/P, A/P disengages "without ambiguity." There's noise. A/T reacts the same as above. F/D will initially command a pitch up, searching for 1000 fpm climb until magenta command speed, present flap maneuvering speed for MGTOQ, then it will hold that speed in the climb. With flap configuration towards UP, the command bug will increase with it. This is the "auto bug" feature. With ALT CAP, this feature stops.
With fully manual flight, it's up to you. F/D will initially pitch up, but will be searching for command speed and eventually pitch down to recapture that speed. If you are rather high or early on the approach, TOGA will work, but the only way out of a coupled ILS is to.... what? Test question here. How do you get out of APP mode? With LNAV, you won't have this problem.
You don' have to jam "radar power" every time you go around, nor do you have to pitch for the sky. Learn to fly without the A/P A/T, and understand what the F/D is giving you.