I feel like this exists but I forgot to bookmark it and I'm having a hell of a time finding it if it does exist (largely due to broken SearXNG instances argh!) In my experience each one I save into Fennec via search string only lasts a few months before it breaks intermittently or entirely. I'd rather use a link that picks one at random and is thus more likely to just return results without too much fiddling.

Yes ideally I'd host my own... it's on my miles long to-do list...