I grew up in the same situation (expect only 1 sibling), and leaving was incredibly liberating. The pain has dramatically decreased, although her “ghost” has not yet stopped haunting me. It was hard for my sister at first that I left, but a little later she also did, partially only because I inspired her and showed her it was possible and worth it. Try to find a way to stay in contact with your siblings, but don’t stay just for them. You may end up helping them more by leaving