If you are in an area or Musjid and the people aren’t used to a particular Sunnah then for the sake of unity and not causing differences that Sunnah should be left.
This is complete understanding of the religion.
Unity is obligatory and the action is a Sunnah and the obligation takes precedence.
So think carefully in front of family etc. Use wisdom. For example, you know saying Ameen out loud will cause problems and no one else does it then say it quietly!
Or you’re praying at home and moving your finger and you know your family will turn it into an issue, and if you don’t do it they are more likely to accept what you say then you leave it! Especially as moving the finger for example has been weakened by a lot of scholars! So you’re doing something which isn’t authentic anyway, creating fitnah with it and putting people off from listening to you!
Think of the greater good.