The more people feel attacked for their view the less they will let go of it. This is why 1on1 in multiple calm conversations you have the best odds of convincing these people. Also don’t argue with logic appeal to their emotional side. People will understand better if you bring themselves into the position. Don’t expect one conversation to change their mind it can only kickstart change.
The thing is this whole transgender or all bigotry discussions are emotional to begin with. Even the rational sounding arguments are just emotional appeals. What you do is you make emotional appeals that also sound logical.