By the way, even if you fully plan to vote for Biden in November (because Trump would be worse and has declared that if elected he would ban Palestinians from entering the US x, x, x, x)...
You can and I would argue should call or email Biden or whatever other Democrats represent you and just straight up lie about it. Tell them "I'm a constituent, and I've voted for you in x number of elections, and thanks to your support for the genocide of the Palestinian people, I will never, ever vote for you again."
Politicians, Democrats, and especially Biden need a fire lit under their asses, because the vast majority of them clearly aren't going to do shit without one. Or, worse, be like Biden and actively be the reason that Israel can continue its genocide on a political, monetary, and military level.
Tell Biden and other politicians that you will never vote for them again. It doesn't matter if it's true. It will help pressure US politicians to stop this genocide, and therefore it's the right thing to do.
Obviously this also applies to other countries where politicians are supporting Israel's genocide, especially countries that have cut funding to UNRWA (list here).