Learn git and how to read/write json files for working with teams and deployment. Create an api to test ,using Postman, your own projects. Not sure you're going to land a BE job due to working with sensitive data, critical systems, etc. If you expect to get a BE job then get gud at auth and working with excel spreadsheets. 2 things that businesses care about are security and reports.
Stay away from js frameworks for building BE systems. Js was designed to manipulate DOM, and that is what it is good for. Angular typescript is a good framework if you end up doing FE work. But i'll repeat, js was NOT originally intended for a full programming environment. It's best used for manipulating web pages.
Avoid jquery if you can help it. That stuff is like debug hell.