If you have the Brave Browser installed on your Windows devices, then you may also have Brave VPN services installed on the machine. Brave installs these services without user consent on Windows devices.
Brave Firewall + VPN is an extra service that Brave users may subscribe to for a monthly fee. Launched in mid-2022, it is a cooperation between Brave Software, maker of Brave Browser, and Guardian, the company that operates the VPN and the firewall solution. The firewall and VPN solution is available for $9.99 per month.
ddg relies on Bing so it isn’t really comparable, idk about kagi’s costs but they claim 1.2 cent per search and an average of 700 searches per month (as what they are serving and hence pricing for)
If you mean has a crawler, ddg does crawl and augments with bing. Kagi doesn’t have any crawler.