Depends, what country are you in? I'd suggest donating to a trans healthcare organisation, because based on my personal experience of being alive, there should be more of those.

Here's some in the UK: https://www.pinknews.co.uk/2020/11/20/trans-charities-donate-funds-donations-transgender/

or, internet search: https://duckduckgo.com/?q=trans+healthcare+charity