Having a minus act like a plus has been particularly tough (for years now, I believe).
I use Google as a fallback but these days it happens perhaps once every couple months, and mostly I don't get anything out of it.
Google remained better for programming questions for significantly longer (I speculate this may be because Google's own programmers used it, and complained when the results sucked :-)), but now it's not. Not really.
Like you, I still use Google as a long shot, but that's become quite rare.
I sometimes use Bing for Microsoft-specific questions, if DDG doesn't give me what I want. I have the sense that Bing covers Microsoft a little better than the others do. I have no real solid evidence for this, but it seems plausible on the surface.
Kagi for me is a no-no. I mostly browse on temporary containers, and also have Firefox delete cookies on close. A search engine that requires me to be signed in would be a massive pain to use.
Maybe its different in the US or just not optimised in Germany, but the quality of search results isn't comparable.
Query: "All you can eat Kiel"
Google:
1. a map with the top three restaurants for this context in the foreground
2: a list of restaurants, sortable by price/date/hours
3 to end of page: links to homepages of the top restaurants
DDG:
1. a completely random assortment of irrelevant links on the left
2. a semantic web box with a 3/5 rated irrelevant restaurant on the right
3. wild youtube-videos vaguely related to the query between text results
4. images
5. more wild links
that kind of thing. And Kiel isn't a small city, we even had DDG print ads here.
When I try your query I only get a bunch of local German stuff (including a map with restaurants).
I admit, I don't even know what Kiel is so I can't validate the results but despite them being in Germany (and my search having had the country selector set to UK), it looks pretty good.
If I search something more generic like "all you can eat sushi" I get a neat map with a few restaurants that do that, plus a bunch of TripAdvisor and other directory and blog posts exactly about that, all local.
If I try your query again, setting the country to Germany, I get https://yummy-kiel.de/ as the first result, a map with top-three restaurants as the second, and again, a bunch of directories and blogs with all you can eat Kiel.
Seems pretty good to me.
I think it's Tay v2.0 injecting itself into the conversation.