I’m not sure what you mean by manual formatting. You do need a place in your program where you fill in the parameters into the respective localized string template. I agree that the printf format syntax is somewhat limited for localization [0]. But whatever localization string format you use, you don’t want arbitrary expressions embeddable within it.

[0] though GNU libc does let you extend it: https://sourceware.org/glibc/manual/latest/html_mono/libc.ht...