For me, a punchy climb is under 2 minutes, and more often 15-45 seconds, and often followed by a descent.
Specifically, something where heavier guys like myself have a shot at duking it out with the smaller guys by going anaerobic and being able to recover afterwards.
Punchy climbs also come in multiples sometimes. Something that mimics TR workouts like Pierce.
A 5-6 minute climb for me is not punchy at all. It’s a torture chamber where at best I can hold about 120-125% FTP and watch the smaller guys cruise by at threshold.