Don't believe a single second the marketing speech about these 2 engines, they are both total crap trying to gain users with whatever hype subject is around.
Qwant used to pretend being a champion of privacy, a "french made" tech, but with a search engine mostly based on Bing, lobbying with Microsoft against our interests, and with a boss sucking as much public funding as possible to finance luxury HQ locations and lavish cars...
Qwant collapsed and was sold, but now it is just a mediocre ghost product trying to capitalize on a stained branding and on being a French/european alternative.