Get clear on your standard for respect, so you catch the very first slip instead of the fifth.

Standards that exist only as feelings get negotiated away one small step at a time. No single moment is bad enough to object to, so it passes, and by the time something is clearly wrong you have already accepted four versions of it and speaking up now feels inconsistent. Knowing the line in advance changes the timing. You get to say something while it is still small and easy to say.

Write down two or three things you will not accept from anyone, in plain words. Keep the list short enough to remember. Then say something at the first slip, while the stakes are low.