I hate the "rewrite it in Rust" mentality, however, I think that in this particular case, Rust is the right tool for the job.

The Rust specialty is memory safety and performance in an relatively unconstrained environment (usually a PC), with multithreading. Unsurprisingly, because that's how it started, that's what a web browser is.

But Tor is also this. Security is extremely important as Tor will be under attack by the most resourceful hackers (state actors, ...), and the typical platform for Tor is a linux multicore PC, not some tiny embedded system or some weird platform, and because it may involve a lot of data and it is latency-sensitive, performance matters.

I don't know enough of these projects but I think it could also take another approach and use Zig in the same way Tigerbeetle uses it. But Zig may lack maturity, and it would be a big change. I think it is relevant because Tigerbeetle is all about determinism: do the same thing twice and the memory image should be exactly the same. I think it has value when it comes to security but also fingerprinting resistance, plus, it could open the way for dedicated Tor machines, maybe running some RTOS for even more determinism.