Seriously this happens all the time, even someone as useless as Harry Kim managed to go back in time and wrench the timeline back to his preferred trajectory. Every single Vulcan survivor would like to see their planet not destroyed. Vulcans are hugely intelligent and given to monomania, one of them being tipped over the edge of deeeep research into obsession seems likely. You know if one of them wanted to either stop the destruction and crush the timelines back together OR jump timeline and exist in the one where Vulcan survives they could. They could totally do it. Might take a few decades though who knows, maybe a whole sect of Return to the Timeline Vulcans will spring up and it will go faster than that. The E2 crew devoted generations to saving Earth.