You have good points and valid reasons to be upset in this election. If we don't see change in this administration now, why should we expect it going forward?
That said, I would like you to consider a perspective shift on the impact of voting. Put yourself in the shoes of a politician. What is your bottom line? It's to get reelected.
If you aren't in a position of power, you can't pass any bills. You can't push any agendas. You can't stop wars. You affect nothing. This is true for politicians, CEOs, Popes, dictators, board presidents, school principles, and homeowners association presidents.
In order to keep that power, you need to make your keys to power happy. In a democracy, there are a lot of keys- those are your voting blocks. The rich, the military, unions, families, students, different ethnicities, different religions- you need to calculate which blocks are most likely to get you reelected.
Now a lot of people wonder why is it that American election campaigns seem to go on forever. They take years. This is because candidates are looking to see who they can bring in to their side. Voters who they don't please go to their opposition.
Let's fast forward to after the election. You have won the presidency and are eager to get to work- but guess what, in 4 years you will need to do this all over again. This time, you look at the blocks who voted for you. These blocks were the ones who successfully got you in power, and you want to keep them happy. It's easier to keep voters than to flip voters, this is the incumbents advantage.
You look at your voting blocks, and you notice there is a large chunk of your previous "supporters" (not that they like you necessarily, just that they voted for you) who want to end arms sales to Israel. If large enough, this group will be pivitol to your next victory. You may have run on a pro Israel stance, but if your electorate needs you to change, you will change.
This doesn't mean protest sit outs aren't effective. Michigan had a large vote for Palestine in Biden's primary campaign. After that result came through, the administration took on more moderate rhetoric. It's empty, but a first signal nonetheless. If this happened in Illinois or Washington State, his campaign would have ignored it, but since Michigan is a swing state, they paid attention.
In this election, I'm voting for Harris. However, down ballot I'm voting for pro-palestine candidates. Trump's voting blocks clearly favor Israel, but Harris has a divide she needs to address, and if she sees enough voters voting pro-palestine down ballot, she is much more likely to change her course.
For a deeper look into power structures and how leaders are influenced, I'd recommend watching CGP Grey's 20 minute video on the rules for Rulers.
There is so much nuance in this discussion that it's difficult to put all counterpoints into a Lemmy comment while I'm sitting on the pot, but I hope this gives you some more questions to consider as you make the bridge between your values, ideal outcomes, realistic outcomes, and pragmatic strategies for getting that done.