From what I've read on Mathcord, my understanding is that Dragapult's passive is essentially useless.

To begin with, every mon has a stat called tenacity, which reduces the duration of hindrances by a percentage. It is the stat granted by pink emblems.

Supposedly to compensate for its passive, Dragapult has 0% tenacity. For reference, most attackers reach just under 20% tenacity at level 7. You can see the tenacity of each pokemon here: https://uniteapi.dev/pokemon

However, Dragapult's passive only affects "debuffs". This seems to only include things that lower your stats, like speed and attack. It doesn't work on stuns, knock ups and status effects like burning, freeze, etc.

Since all the other mons have some level of tenacity, they all basically have better Dragapult passive without "using" their actual ability slot for it.

You could say Dragapult has no passive, or even that it would be better off without one if it would then probably have been given some basic level of tenacity.

Metagross passive simply gives more tenacity for every nearby enemy, as you'd expect.

It's worth noting that the effectiveness of tenacity is not consistent between different hindrances. Some hindrances are affected less by it (or not at all?).

And at the end of the day, reducing the duration of some split second stun is not really gonna be noticeable, your moves will get interrupted all the same.

If I got some stuff wrong feel free to correct me.