I wanted to understand why Ada is not used in systems programming if it's so great, and found the answer:

,,Ada developers either use a garbage collector, or they avoid freeing memory entirely and design the whole application as a finite state machine (both of which are possible in Rust, too, but the point is you don’t have to).

Of course, Ada has range-checked arithmetic, which Rust doesn’t have (it needs const generics first before that can be done in a library), so if you’re more worried about arithmetic errors than dangling pointers, then you might prefer Ada.''

For me not freeing memory sounds like a joke. It's the opposite of zero cost abstraction. Regarding GC there are lots of great languages already (for example modern Java).