Exactly this. I (relatively recently) joined a team with a handful of developers all sort of doing things their own way. No docs, no shared practices, just individuals doing their own thing. After reviewing the code, submitted PRs with fixes, putting together docs for best practices, the entire team shifted their stance and started working closer together in terms of dev practices, coding styles, etc.
Not to say I got everyone to march to my drum -- the "best practices" was a shared effort. As you said, sometimes it just takes someone to call things out. We can do things better. Look at how things improve if you approach X problem in Y manner, or share Z code this way. Maybe the team was overwhelmed before and another voice is enough to tip the scales. If you don't try, you'll never know.
Not to say I got everyone to march to my drum -- the "best practices" was a shared effort. As you said, sometimes it just takes someone to call things out. We can do things better. Look at how things improve if you approach X problem in Y manner, or share Z code this way. Maybe the team was overwhelmed before and another voice is enough to tip the scales. If you don't try, you'll never know.