If you’re just worried about them knowing you visited Duckduckgo (Just like your ISP knows), use a VPN or use Duckduckgo’s Tor hidden service.
Let me know if I’m missing something... but I can’t see how Amazon can track your DDG usage just because DDG uses AWS.
And joking aside, I honestly wouldn't put it past someone like Amazon to find a way to slip something into the service without DDG noticing.
It's wouldn't even be the first time something's been joked about only for some pillock to make it a reality.
Private residence of Jo Jerrica Decker.