(The borrow checker does not understand locks as a special construct, to be extra clear.)
Did you read the post I linked? It lays out the details. I am happy to clarify if you don’t get the specifics.
Sorry, my mistake!
Edit to add: futures work badly in every language, so there's no shame in the borrow checker not working with them.
Edit 2: But in that case we're back to "why would Rust want async/await over (potentially green) threads with its first-class support for locks?"
1. Rust's Journey to Async/Await - https://www.youtube.com/watch?v=lJ3NC-R3gSI
2. The Talk You've been Await-ing for - https://www.youtube.com/watch?v=NNwK5ZPAJCk
The first video goes into all the bits you're concerned about and all the things that Rust has tried before arriving where they are now
Tokio basically is green threads as a library.