It's mostly changing orders and taking things out of the hot path:

• precomputing the parsed query once and reuse it
• taking regex constants out of the hotpath
• first filtering results and only then sorting them
• caching of the lowercased query string
• existing the search loop once we know that the result buckets are full

PS: I'm looking for a new adventure in case anybody is looking to hire or work with a PO/PM or Ruby/Rails/Crystal dev