Data on search engine market share is available, but I wonder what that looks like for Lemmy users in particular, who I would assume lean more technical than the average user, so probably use DuckDuckGo and alternates more than Google.

I use a mix of DuckDuckGo and Kagi. I'll also use ChatGPT, which can be good if you're careful to verify the answers it gives you as a check against hallucinations. It's useful for short, direct answers without ads or SEO bullshit.

This article on Ars (and if you're not a subscriber, you absolutely should be, as they are the best tech journalists out there) inspired the question: https://arstechnica.com/gadgets/2023/06/google-admits-reddit-protests-make-it-harder-to-find-helpful-search-results

Fucking Reddit. Enshittification ruins everything.