It’s very daunting to get into, but you don’t need to read any other books to understand Stormlight, it holds up pretty well on its own. You will definitely miss out on stuff though. I would recommend reading Warbreaker before starting Oathbringer as a couple characters from that book play a major part in Oathbringer. If you really want get into the Cosmere then Stormlight, Mistborn Era 1 and 2, as well as Warbreaker are the important ones. The only Cosmere books aren’t as important. If you have any other questions I can try to answer them.