For example, the Pony language is written in C and guarantees no races or deadlocks without using locks or mutexes so it's faster than C with locking. The user defines intentions, similar to Rust's borrow checking, and strict compile time analysis makes it happen for you.
This claim is misleading. The reason why Pony is able to "guarantee" no races or deadlocks is because it doesn't support shared memory concurrency. If you are willing to give up shared memory concurrency in C you can achieve exactly the same performance.
In fact, you often have the opposite: shared memory concurrency (implemented in languages like C) can often offer performance advantages that actor models like Pony can't provide.
Doing this with an actor model would be tricky to the point of impossible. Sending a message to the common "dictionary" actor is much, much, much less efficient than just holding the corresponding sharded lock.