You aren't really contradicting me, I agree that Rust isn't a great language for prototyping. However, there are some solutions that help with prototyping, namely: judicious use of Clone‚ Arc, Rc, and unsafe.
In particular, if your comparison point is C and Zig and you don't care about safety you could use unsafe, knowing you are likely triggering UB, and be in mostly the same position as you would in C or Zig.
Let me be more clear: the cognitive overhead is real, and does go away with less constraining languages. If that doesn't disagree with your previous point then I misread it.
And I was making a point even more general than prototyping, though I also wouldn't discount the importance of that either.
In particular, if your comparison point is C and Zig and you don't care about safety you could use unsafe, knowing you are likely triggering UB, and be in mostly the same position as you would in C or Zig.