As a previously front-end gone full-stack gone and settled in backend/infra… don’t bother. But if you have to bother, or really, really want to 🙂, pick a relatively popular thing (e.g. Vue), and learn that, ignore the rest. By the time you come up for air the new hotness will have changed anyways, and the wheel will have been reinvented twice. It’s a moving target, just learn the fundamentals with something and you’ll be good to go.