mike_mike you're doing good work. This could beat the chinese 0-30V 2mA-3A power supply kit, which would be a relief to us all.
I haven't contributed and don't want to upset things, so take all this lightly. You could polish this design, or keep experimenting.
C2 and C4 give a variable time delay depending on the potentiometer's position. I find you can get instability at low (V or I) potentiometer settings, made worse by the Sziklai having higher gain at low currents (beta droops at higher currents). Q7 needs to be flipped C-E?
I would consider changing the architecture, so the CC op-amp cannot affect voltage-setpoint accuracy.
U3's output voltage (high) will not be consistent. In CV mode, U3's output will sit saturated high and will move around with temperature and mood, so the voltage setpoint will be a bit drifty.
Also, CC mode includes a second delay of the CV op-amp. So CC mode transitions go through two stages- which is overall slower.
The 0-30V 2mA-3A power supply kit, the CC op-amp instead pulls down U4 (+) input.
Other PSU designs the two op-amps instead drive Q1 through a diode/transistor OR gate, where either (V or I) op-amp can fast control Q1. CC still has priority over CV of course.
I'd have to play with the LTSpice .asc and see if I can contribute anything.