I sing in a chorus and my church choir, so I'm pretty conscious of my voice.
I started HRT (estradiol and spiro) at the beginning of November, and by December, I noticed that my vocal cords felt "thicker." It feels like I've got a layer of mucus on them. My voice hasn't changed in range, but the quality has changed: it sounds like I've got a cold. And it's harder to get them to start sounding. E.g., when doing the usual vocal warm-ups, where the chorus or choir director tells us to sing as softly as possible, I can't sing anywhere near as quietly as I used to. I also keep reflexively clearing my throat in the hopes of cleaning off what I somehow feel is on them, except it doesn't help, it just makes my throat feel raw.
Has anyone else noticed anything like this on HRT?
Only a guess but the Spiro might be drying you out. You might need more fluid intake in order to keep your vocal cords moist.