Hi !
It's so wierd that so much people seems to have loading issues with Qwant cause I have none. I tried on ungoogled Chromium, Vivaldi and Firefox (both desktop and mobile with FF) on cabled internet and wifi and still have no problems.
I will try to communicate this issueto the Qwant team on their official Telegram group (ps: I am not a Qwant's staff member).
Meanwhile, have you tried lite.qwant.com ? It is a javascriptless version of the search engine. Maybe it will be better.