Plane: auto mission that goes at 90 degrees UP/Down, possible?

I’ve tried to plan auto mission that can do some acrobatics with my plane like going up or down at 90 degrees.
The problem is that ardupilot by default achieves the waypoint when it gets-in within the waypoint radius and does’t consider the alt, only lat/lon and radius. So when I set two very near successive points with different alt, even if I’ve increased the max bank and pitch to -+90 it just moves few meters then goes to the next point as it’s already within waypoint radius.
So is there a way to change this behavior? If I have a capable plane, of course.

Not currently supported, as you said. Altitude is only enforced in loiter_to_alt command. Do you have any interest and programming skills in changing that behavior?