If your main concern is trans rights, your options are extremely limited as most countries in the world are worse off than solid blue/Democrat states in the USA, on this issue. Getting access to trans healthcare and those important things would be very challenging in most "global south" countries. I wouldn't recommend South Africa, while on paper LGBT rights are well protected, the reality is different and you'll be forced to have a good private healthcare plan, called a medical aid. If you're earning US dollars or Euros you'll probably find our private healthcare really cheap compared to the USA, but if you're earning a salary in South African Rands (ZAR), the private healthcare here is very expensive.

If you are currently living in a red/Republican state, swing state, or a Democratic state that is not good on trans issues, a more realistic plan would be to move to state that is protective of trans rights as a start. It's much easier than moving to an entirely new country, I would assume. If you already live in such a state and want to leave the USA (very understandable), you'll have to research countries that have good protection of trans rights, on paper and in practice, with affordable access to the healthcare you need. I imagine this is going to be a pretty short list of options, mainly consisting of Western European nations, and maybe New Zealand or Australia.