I feel you're going on a massive leap. The medical science does not yet exists to transplant my womb or eggs into a biological male and then get it to work.
Is it though? We now have the science to induce artificial breastfeeding in trans women. Even if it was, why wait for it to become a reality before fighting it?
50 years after I die the ants could take over and decide to use what's left of me to feed their ant babies - I can write in my will that I'd rather not be ant baby food but I can't really stop it.
Well no because that's nature, it would be like saying you don't want your body to decompose. It is a natural outcome. Having somebody harvest your reproductive system to create a Frankenstein surrogacy is within your power to change.
If I died and my womb could be used to carry a baby in a person that would otherwise not be able to carry a child, be them born Male or Female, I would be happy to oblige
Well that's you. You would only be able to sincerely hope you are not participating in the creation of a child that would have serious health and social implications as a result being carried in a body not designed for it.