Well ok so I'm not a miracle worker which is why my go to advice is to uh.... Fucking leave. Unironically. There's already a couple sanctuary states for trans refugees like New York, California, Washington state, and Washington D.C.
If this passes and trans people start getting arrested, then fleeing is your best bet.
I know this isn't feasible for everyone, however. So, what I would recommend is stockpiling up on estrogen. Estrogen is legal to buy without a prescription. It's a grey market.
Here's a few resources to get started with that:
https://diyhrt.cafe/index.php/Main_Page
http://lena.kiev.ua/ev/
Now, testosterone is a controlled substance and cannot be bought without a prescription. It is a felony with a maximum of 25 years to be in possession of testosterone without a prescription. More trans mascs than trans femmes will die of these laws due to this and should be prioritized. Also keep in mind the reproductive healthcare is constantly under attack as well and we can easily become pregnant without our testosterone. Though testosterone is not birth control and you can become pregnant on testosterone. It's just less likely.
If this bill does pass and people over the age of 21 want to access medical healthcare then they are going to have to lie by default. None of this "Oh well things are different now, WT" bullshit. Lie, lie, lie. You are a binary straight trans person who has been thinking of living as your gender since 5 years old and refused to play with toys associated with your assigned gender. I don't care what you are truth is. The doctor will not treat you unless you lie.
And when you go to the doctor, make sure that's what you're presenting as. Become a stereotype for that first visit.