Love that you're calling it a "marketing site"
Indexing is meant to be as fast as possible. It's good enough for my needs. You can add custom folders and/or their contents to the global index. Which I think would be the equivalent of "in" search?
Swift. I'm currently dog-fooding the implementation for many of the built-ins and the store downloadable ones. I want to let the API and approach settle a bit before making it public but they'll be Swift based and hopefully easy enough for someone experienced in any kind of programming to implement with the help of an AI agent or on their own.