The fastest way to lose a team is talking about one player to another.

Everyone you confide in about a teammate learns two things: what you think of that teammate, and that you are willing to do this at all. The second does more damage, because now they are wondering what version of them exists in your other conversations. Confidence drains out of a group that way with no single dramatic event. The chat feels harmless while you are having it.

Take your problem with somebody to that person, not to the person next to them. If you need advice, describe the situation without naming anyone. When others start, decline rather than nodding along.