I tried adding a homebrew feat from the public list to my collection and hoped I'd be able to select it as a template when creating my own, but that didn't work.

Is this not possible, or did I just miss something? Having to recreate something from scratch because it just does *almost* what you want is rather annoying... :/

No, it is not currently possible to use someone else’s Homebrew as a template for your own. Try contacting the original author, maybe they can help with an alternate version for you. If you two join the same DDB campaign together and they send you the URL for it you will even be able to add it to your collection without their having to publish a second version.

That seems like a pretty bad option. Why would I want to cause additional work for someone else if I just want to fix e.g. a typo or make some minor changes that may be unlikely to be useful for others?

I just can't see any good reason to have a "closed source" approach for this...

Because it’s someone else’s work, and there’s no way to have the system automatically scan to see if your new version is “too similar” for publication.

Easy solution: Do not allow publishing copies from homebrews, or keep a "based on X" there to always have credits?

🤷‍♂️ That would be better as a suggestion DDB in the feedback forum. I know they mentioned that they planned to allow public homebrews as templates, they just haven’t done it yet. (Who knows how long it’ll be before that makes it to the top of their to-do list?)