How do you manage flakes in large repos?

I like flakes, and I would like to use them as much as I can, but they slow things to a crawl when the repo is very large. I recognize that lazy-trees will improve the situation, but I can’t wait on it.

Are there any practical ways of making flakes work with very large repos right now? I recognize that they might be hacky, but as long as they’re practical, they’re worth mentioning.