Colombo, not all allied rides had automatic mixture controls, and the workload in Russian aircraft was tremendous. When you engage WEP it's just a push of the button in AH, but in real life it was in many cases a much more complicated task of setting mixture and RPM controls, often according to altitude as well. Some early war fighters didn't even have constant speed props or automatic cooling systems. The 109 and 190 were special however, as they were completely HOTAS except for trim in the 109. The 190 was unique in that it didn't need any change of trim during combat maneuvers, even in dives.
Here a Yak-9 cockpit. Look at that throttle quadrant.
Fw 190 for comparison. Single lever regulating throttle, RPM and mixture via an electro-mechanical computer. Also electric push-button controls for flaps and trim located nearby.
As for using flaps in combat:
Me 109 F/G:
"- Did pilots like the slats on the wings of the 109?
Yes, pilots did like them, since it allowed them better positions in dogfights
along with using the flaps. These slats would also deploy slightly when the a/c was reaching stall at higher altitudes showing the pilot how close they were to stalling.....this was also useful when you were drunk "
- Franz Stigler, German fighter ace. 28 victories.