If you just want to blend in with the crowd, you can use the tor browser without the tor proxy.
They have invested a lot of effort crafting its fingerprint. Now that they have moved away from Firefox ESR, it shouldn't come with much of a security penalty.
That's beyond DuckDuckGo's control since that data is controlled and sent by the browser.
There are many addons for doing what you said though just look for user-agent changer or faker
Startpage's private browsing feature does something similar but far more effective.