dio was never shown to chain timestops either, even at his peak Jotaro gets him by waiting his timestop out and freezing him there, he does it multiple times actually. Dio has a longer timestop length, presumably because he’s a Vampire (though this isn’t directly stated iirc), but the length he can stop time is the only solid difference. Diego with The World could also only stop time for 5 seconds, which implies it’s a human limit but again, that’s speculation afaik also the stand profile says the 5 seconds of time stop are roughly equivalent to “normal human time” so I’m not sure why the cooldown being stated to be seconds also wouldn’t be. But I already acknowledged twice that if it is more based on stand user pov then it wouldn’t be an issue. It just doesn’t change that there is still a cooldown in general.