Yes they were, both Zen 2 and frequently Zen+ and Zen were good at gaming.
They weren't great at 1080p gaming with a 6900XT. Which didn't exist yet. And if you're using a 6900XT at 1080p, you're doing it wrong.
They were OK at gaming with a 2080Ti at 1080p (also a waste) and only slightly behind at 1440p, but if you're spending $1200 on a GPU, just get the best gaming CPU which was Intel at the time. Once you get to a relatively normal higher end setup like a 2070 Super at 1440p, the 2600x or 3800x were only a few % slower than Intel, which would not be noticeable in-game.
That is *good* in gaming.