From the blog post, it sounded like their benchmark relied heavily on a gem with a C extension (nokogiri). It's hard to imagine a performance improvement on code that YJIT has no control over.
Yes, we ended up replacing Nokogiri by Nokolexbor, our own port of lexbor parser with like almost full compatibility with Nokogiri APIs while being around 5x faster: https://github.com/serpapi/nokolexbor