Not really understanding what this would be though, zig has all the basic stuff you would expect in its stdlib (hashmap, queues, lists etc) just like Rust

This is from last year, the stdlib was much more bare back then.

Then it's actually the immature zig ecosystem that rubbed the author the wrong way, not zig the language itself. Not that the ecosystem isn't important, but IMO a language only truly fails you when it doesn't offer the composability and performance characteristics necessary for your solution.