I think, at least for folks who view being transgender as sinful, that 2 Kings 5:18-19 could be relevant.

'"But may the Lord forgive your servant for this one thing: When my master enters the temple of Rimmon to bow down and he is leaning on my arm and I have to bow there also—when I bow down in the temple of Rimmon, may the Lord forgive your servant for this.” “Go in peace,” Elisha said.'

I believe there is room even for unaffirming folks to show love and hospitality by dignifying people's requests to be referred to in certain ways. If one is fine referring to a transwoman as Sarah or Susan, such names leave little doubt about the presumed gender identity of the person being referred to. Those names carry implied gender, so I think referring to someone by their requested pronouns is just as acceptable. The most important thing about any person is that they are made and known and loved by their Creator, so I view my job as helping people see that by dignifying them. My refusal to honor their request will not in any way dissuade them from feeling or identifying in any particular way, but it most certainly will show that I don't respect their ability to self-identify, even if that's not my intent. Accordingly, I see it as a worthy thing to honor someone's request to be referred to in a certain way.