FWIW, Privacy One Group Ltd has "invested" in Startpage since January 2019. Privacy One Group Ltd is a separate entity operated by System1, an advertising company. Startpage does still seem to get regular 3rd party audits to keep everything in check though.
More info on this can be found in this reddit thread: https://old.reddit.com/r/privacy/comments/di5rn3/startpage_i...