Personally, I have replaced most of the DDG bangs with firefox keyword searches. As long as your target site accepts the search string as part of the url, you can achieve the same thing without any search engine redirect.
That's true, but I don't use all 13,000 bangs. It would be impossible for me to remember that many anyway. I should have said "the bangs that I actively use" instead of most of them.
Looks like I have 32 keywords bookmarked like that, around 20 of which I use regularly. The search url's are quite stable, I don't remember ever having to update one. But I'm sure it will happen occasionally.
In practice you don’t use that many, and also for most of what I use I’d have to create additional custom “bangs” anyway. For me it’s a browser-level feature (this has been present in browsers from very early on), independent of which search engine I use. And unless a search prefix actually maps to a search engine search, the search engine service has no business of knowing what I query. Better keep it separate.
As an example, my python search bookmark:
Means that I can type ctrl-L py and it does the same thing that ctrl-K !py used to do.