ubo is more featureful, while privacy badger is simpler. ‘better’ depends on needs. i’ve used both, even at the same time for some redundancy (at the expense of memory/cpu time).

privacy badger (if i’m remembering correctly) is based on ubo but specifically curated for privacy (not ad or other blocking), and as such, does most of the customization for you, whereas with ubo, you need to do much more of the customization manually.

so to answer the original question, i think privacy badger, like ubo, does use some dynamic rules, and those would be relegated useless with manifest v3.