When it comes to metagaming being problematic in some way, I generally think that if that's the case, it's largely the GM's fault. This isn't always the case, and I think there are several factors that play a part, but generally speaking, if you as a GM don't want your players to use metagame knowledge, then don't present them with situations that involve doing so.
I just see it as kind of oxymoronic. Like, if you're worried about players having an unfair advantage due to metagame info, then it seems you care about RPGs as a game... which means you are likely interested in testing player skill. Asking players to not use knowledge they have is counter to player skill... it seems less about the game than it is about the integrity of the fictional world. And if that's your chosen focus... that the fictional world be consistent and have verisimilitude... then it would seem that allowing player knowledge to influence the fiction would facilitate that. That there would be some in world reason to explain why the characters know what the players know.
The motivations against metagame info influencing play just seem confused.
Plus, very often when these things come up in play, the metagame information is still influencing things even when it's not being "used" by the players. So if there's a monster weakness that the players know, but the characters don't, then not allowing the players to deploy attacks that target the weakness (fire vs. trolls is always the example, but it can be anything) is still a case of the metagame info interfering with play. What if a character may have guessed the weakness, or used an appropriate spell or attack that would have revealed the weakness? Not allowing them to do so is just as much metagaming as allowing it. If there is not some system in place to account for this and make it part of the game (and often even if there is) then it's arbitrary. It's the GM making players jump through hoops.
So yeah, although I think there can be exceptions... there may be times when it makes sense to somehow not allow out of game information to be used... I think those are more the exception than the rule. The reasons to do so are just confused and inconsistent and let's be honest, pretending to not know what you know just for the purpose of preserving or prolonging an encounter is boring play. Give me some other way to engage with the scenario that will be interesting instead of relying on the metagame element to make it so.