myself, as a cishet dude, to be telling trans people in the US that the negative outcome here was coming either way?

Are you being asked? Because I generally would not assume that trans people would either ask you, as a cishet, or hold unsolicited advice from you on this topic in high regard. I'd suggest just focusing on other issues.

First of all, it's good to show empathy. A Trump presidency is scary for every trans person that isn't Caitlyn Jenner levels of privileged. That doesn't change the fact that the Biden admininistration did literally nothing for trans people, or that Kamala refused to even performatively pay lip service to our struggles, or that Democrat support for our rights happens exclusively on the state level and isn't reliable even there. It's a party scared of standing up for us and ready to throw us under the bus at a moment's notice. But having the people who conducted the early stages of trans genocide on the state level now in charge federally does make a difference, even when it's the difference between standing by idly while we are hunted or actively endorsing that hunt. It's even felt here in Europe. I have a friend with family in America who is scared her loved ones might get deported, i have another friend who planned to get a type of bottom surgery only available in the US and who just realized this may no longer be an option for her. These news hit very close to home and that should be recognized.

However, it's also important for trans people to understand that voting was never going to save us. We need to fight on other fronts, we need to organize, form mutual aid networks, build coalitions with other groups that are under increased threat now, go out and protest, agitate etc. etc. We particularly need help from cis allys. Listen to what worries us. Maybe trans people around you need help getting out of state, or know people who plan to move to your state and need practical support with that, from having a place to crash to finding a new home to just having somebody there to unload furniture. Many people are struggling to pay for gender affirming care, or may have to travel out of state to even access it. Even if you do not know trans people irl, there will be situations where you encounter transphobia. As a cishet dude, you can push back against that without being worn out by it the same way we are. Use that. I've heard way too many stories about friends getting insulted or assaulted and nobody was there to step in. Be that guy when you see something. Speak up when you hear something. These are times of struggle and we need every man, woman and nonbinary person who's willing to fight on our side.