Its disturbing that you think that writing to US politicians is influence but not surprising. You know I was a anti-poaching ranger right? I was in the thick of influence campaigning and this kind of this required photos of when that politician's penis accidentally fell into a rent boy. You need leverage, not sincerity.
Actually contacting your politicians about issues can influence policy and drive changes. Especially if a large numbers of people contact their offices. One note of interest from the article at the above link is that "U.S. senators pressed the country into resuming aid because they couldn’t tolerate images of extreme hunger coming out of Gaza. They suggested that if such hunger were to continue, it would affect their support." As I outlined earlier, Senator Thom Tillis (R-NC) has advocated for allowing food aid to be let into Gaza and has stated that Trump's plan to relocate Palestinians from Gaza is a non-starter. Now it is time to contact our North Carolina Senators again outlining the failures of GHF to effectively distribute food in Gaza and that a new approach is needed. Seeing that the U.S. government is funding GHF, this is a very much a situation where U.S. Senators can drive changes. I will note that Senator Tillis has fallen out with Donald Trump over his recent votes and advocacy... and will not be running for re-election.
Note that and really take that in. Actually making change, not just wagging a finger, is work. You want to move people like the Stephen Miller-aligned Israeli hardliners? You cannot but you can provide a little push. You need leverage. Legal, social, reputational, financial. I’ve seen it firsthand, someone local sending criminal menaces to a UK citizen/employer and her friend, ended up under prosecution. Both victims pressing charges though this is a lot effort. That alone gives you leverage, maybe not useful for you personally, but someone in the cause knows how to use it. That’s how influence starts, with consequences.