I think, we should aim first to have a publicly available, reliable and customizable formatter. For example, if LFortran could take a toml-like config file with the most important parameters being user configurable. We could then provide config files for various styles (and maybe even give them names). But more important, every project could provide its own formatter config file, according to the taste of the developers.
Agreeing on a widely adapted standard should turn out to be difficult, there are way too many projects with way too many differing formatting style.