Can tank JG carry?

Hello, currently bronze 1. I am struggling to climb. I play Sej and Shyv. I farm, gank like crazy and build tank so I can try and cc for fights. I usually start out strong but find myself and the team losing late games when it comes to team fighting. Consistently, either my mid or adc split pushes, or tries to ward enemy jungle and dies. This leaves 4v5 fights in which enemy carry shreds us. As a tank I feel worthless when I cant get my carries to cooperate or focus enemy carries in fights. What should I be doing different. Do I help the one solo champ split push? Or should I just build full damage with this champs and try to split or carry myself? In a bit of a slump and looking for any advice. Thanks in advance.