FWIW we did two pretty extensive proof-of-concept prototypes (one in pure C++ and one in Rust) before choosing Rust for this project. I, personally, thought that we would choose C++. I'm a big "choose boring technology" advocate. [1]
In other words, we tried hard to document a lot of before-the-fact rationalizations to go with the inevitable after-the-fact rationalizations. :-)
[1] https://mcfunley.com/choose-boring-technology