>audio device with planar driver demands higher power

That's not always the case. For example, Avantone Planar is very easy to drive.

>how to determine the requirements to drive certain devices

You have to find out how much power/voltage your source provides at the headphone's impedance. That's not always easy to find out as manufacturers usually specify only the power at a few standard impedances. Or they don't mention it at all.

When you know the power/voltage, you can use the power calculator to find out how many dB can it push. 110dB is considered the minimum to drive headphones loud enough even with the HDR content.

But that's only speaking about power. At the end of the day, power is only loudness. There are other things that determine audio quality and you can't just read them off the specs.