I don't think sinking this aid vessel would do anything to change the public conversation. The people who are aware already either condemn Israel or support the genocide. The unaware will not care about a handful more dead innocents.

The bottom line is that Israel is openly and proudly committing atrocities and the international community is not willing to stop it. Only a military intervention could dissuade the IDF.

I wish I could agree with you, but the situation in Gaza looks more and more like something we've seen before. After the end of World War 2, the world reacted with shock at what had been done to the Jews - murder has never been committed on such a grand scale and in such organized fashion. Jews had been dehumanised in public long before, being equated to rats and other vermin. The Zionists currently holding on to power in Israel are using the same kind of rhetoric against Palestinians. However, one difference between then and now is that the Rwanda genocide taught us that the world is entirely capable of sitting back and watch the horror unfold, even though we're all fully informed of what's going on. A ship of brave volunteers being sunk would cause a stern letter or at best sanctions. Israel can act with utter impunity as long as they're backed by their big brother Uncle Sam.

Also a great way to interconnect the climate and Palestinian struggles

If they hurt Greta I predict there will be a lot of backlash due to her fame and popularity.

There will be a lot of "thoughts and prayers", a lot of "how dare you", also lots of "this is a diplomatic incident" sprinkled with maybe sanctions if ever... and that's it, just words.
I hope i'm wrong.

Hasn't her fame faded a bunch in recent years though?

Also, if executing medics, responders and children won't cause a scandal, this won't.