Sometimes you outgrow friends and nobody did anything wrong. The path just forked.

Friendships can end without anyone behaving badly, and hunting for the villain in that tends to create one. People change at different speeds and in different directions, and shared ground genuinely runs out. Accepting that is harder than blame, because there is nothing to argue with. It is also more accurate and much less corrosive.

If a friendship has thinned, resist building a case for why. Let it become what it is now, which might be occasional and still warm. Leave room for the path to fork back.