I agree on Matthew, but other verses talk about this, e.g. 2 Corinthians 3:12. Lying is never ok barring exceptional circumstances (to save a life, to be a spy), not to avoid offending people. To be clear I have a vested interest both socially and by my natural liberal and people-pleasing dispositions to just say otherwise. I truly don't think I can.

You're right about sex, but you confuse gender with gender identity. They aren't the same thing. Gender is how you are treated based on (perceived) sex categories, gender identity is what you're referring to.

I also don't deal with people's gender identity in everyday life, I deal with what I can see about their secondary sex characteristics and gendered presentation.

If I think there's a clear mismatch between their secondary sex characteristics and their presentation then I can't lie and say they are what they present themselves to be.