DuckDuckGo and a VPN are not similar.
DuckDuckGo focuses on its secure web browsing capabilities like a search engine, Chrome browser extension, and mobile browser. It can take steps like keeping your search history private and not allowing site cookies to track you online.
A VPN protects all of the data you send and receive on the internet from third parties on your network, like your ISP. The VPN is a private network that creates a secure and protected connection. It hides your IP address from apps and websites and prevents your internet provider from monitoring what you do online.
Ultimately, there is nothing wrong with using both a VPN and DuckDuckGo in tandem to gain a high level of online protection. The VPN encrypts data in transit to and from your device and hides your IP address, while DuckDuckGo makes your web browsing and searching more private.