I always advised juniors that if they are right, to first, make double-sure they are in fact right, and then it does not matter if the said “toxic” leader outranks them, because nothing outranks doing the right thing.

You prevent bottom-up toxicity as well by being transparent, engaged, present and setting the tone for the climate, as an officer often does. You won’t inspire everyone, but the more engaged you are, the bigger population you influence to sing to your tone and the outliers become ever more evident which you can then engage and motivate in several other ways, not always through counseling. Sometimes have a genuine talk and ask what is going on with them, they’ll see a caring leader.