Doesn't martyrdom imply, um, death?
I don't care about the specific politics, and I don't know his biography. You can love this man and hate China with the power of every cell in your body. But calling anyone a martyr, even with poetic license, has very specific connotations which don't seem to apply here.
Would you be you happier with "soon-to-be-martyr" or "martyr-in-the-making" ?
Not necessarily:
https://dictionary.cambridge.org/dictionary/english/martyr
> a person who suffers very much or is killed because of their religious or political beliefs, and is often admired because of it
https://www.merriam-webster.com/dictionary/martyr
> 2: a person who sacrifices something of great value and especially life itself for the sake of principle