Once enabled, Firefox Suggest sends what I type in the address bar to Mozilla. There it gets augmented with my location and makes its way to their "preferred partners", limited, for the moment, to a lovely establishment called "adMarketplace".
You don't see a slightest problem with that, no?
Reading through their "how Mozilla handles data" page [1] reveals absolutely nothing specific. What's collected, what's being passed on, etc. Just a bunch of hand waving and "don't you worry, everything is tip-top".
[1] https://blog.mozilla.org/data/2021/09/15/data-and-firefox-su...