I think there's been a recent change to tag-badge styles in dark mode that in my opinion makes those badges look less appealing that they used to. I recall tag-badges used to have a deep dark look to distinguish them.
There's now a border around tag-badges, they look slightly smaller compared to regular badges, and they give the impression of a depressed HTML button.
Shown in screenshot:
(I don't have a screenshot of how it used to look for comparison, neither could I find one in the dark-mode threads.)