No, he's not. As much he's effeminate, and two/three throwaway lines imply that he might be an eunuch, but nothing states that he's anything but your typical sissy villain.
(Cordelia ain't trans either. She wouldn't be able to have Severa and potentially Morgan if she was a trans woman.
Then again, unassumingvenusaur (sp?) IS the person who made the infamous FE Awakening and FE Fates ~gay hacks~, so of course they grossly fetishize everything LGBT+ and treat it as ~cute labels to use as accesories uwu uwu~.