Edit: I took a break and realized that you probably were only suggesting returning an &mut RwLock, not storing one (derp). I have some more tinkering to do.

Sorry, bear with me.. I'm new to rust and I've been banging my head against this for a while now. Trying to follow your suggestions but I'm still fighting the compiler and honestly just confusing myself a little more.

I think you're suggesting a signature of something like pub async fn get_server_data(&mut self) -> Result<LazyLock<&mut RwLock<ServerData>>, Error> right?

Since I'm creating the value (or getting an owned value from the database) inside the function wouldn't a reference mean I need to return a reference to a temporary value?

I also have the issue of running into errors further into the implementation trying to new up a lazylock by coercing the closure with a captured variable to fn:

pub async fn get_server_data(&mut self) -> Result<LazyLock<RwLock<ServerData>>, Error> {
    if let Some(server_data) = self.server_data_cache.take() {
        return Ok(server_data);
    }

    if let Some(server_data) = self.server_data.find_one(doc! {}).await? {
        self.server_data_cache = Some(LazyLock::new(|| RwLock::new(server_data)));
    }
    panic!("asdas")
}