My potentially controversial take is that metagaming is neither good nor bad. A metagaming problem is really just some other problem that rears its head through metagaming.

You can metagame and be a good player. It’s like doing improv with dramatic irony. If you’re prioritizing the gameplay and everyone’s enjoyment, it’s a useful tool.

If you’re using it for the personal advantage of your character, though… that can also be fine. Some old-school games, especially dungeon crawls, are like strategy games testing the players as well as their characters.

It’s when there’s a disconnect between how people are playing the game that you get problems. If someone wants to play a strategy game while others want to play improv, and they’re not thinking about what kind of approach is appropriate and when, that you get issues.