No, we must go simpler.
left-pad: you need to account for wide characters, such as CJK characters but also emoji, you need to account for things like combining characters, etc. left-pad is not some trivial function.
Of course, the infamous left-pad package was widely mocked "why do you need a whole package for such a simple task" — so simple, indeed, that it failed to handle many of those cases. But don't worry, it's been standardized now as padStart() … and still fails those cases:
> 'e\u0301'.padStart(2)
'é'
So then, Go issue #4594, "add a Round function [to Go]"[1]. Go maintainer Ross Cox suggests that "it's a one liner" and suggests … a buggy implementation. There are a total of no less than 6 different implementations in the issue, and every single one of them is buggy. The bug is closed, the function is "too simple" to add. Thankfully, the wound gets reopened nearly a half-decade later in #20100. Another buggy implementation is suggested in that thread, and thankfully, Go gets a round function. (A non-buggy one … I think.)