In the past you had to learn a lot of languages and platforms and you still need it in some cases. But for my particular needs, i've managed to narrow down mostly to 2 languages: C++ and Swift. But thats for me, for others it will be different things.
But dont try to find the perfect language.. dont be a hostage to any tech suffering with stockholm syndrome with a given piece of tech.
This weird trend of one tech-fits-all started back in the nineties with Java, with things comming out straight from the religions like 'evangelism', and calling people infidels for trying different things.
Maybe whats work for me will work for you too. I bet you can narrow down to 2 langs to do almost anything you want.
About C++ vs. Rust; Fear not. Modern C++ can basically 'anotate lifetime' in methods contracts by using smart pointers and move when you need. I prefer the C++ approach, have no problems with leaking, lifetime or whatsoever and deal with very large codebases programmed by large teams.
But of course, if i were to create a program to control a nuclear reactor or a submarine i would consider using Rust or Ada. But particularly i find Rust programming more stressful than C++ without (almost) nothing to gain. And on the language design aspect where Rust is superior to C++, i prefer to use Swift if i can, which i consider 'a better Rust'.
By the way in a lot of cases you might consider using Rust or C++, you can use the joyful Swift. Using a powerful language with less of a burden.
TLDR; Where some people will try to use Rust for everything, i prefer to use a Swift/C++ combo, and given you can mix both without much problem in a single program, i hardly need or miss anything else.