What software engineers do? is this a better designation than a Web or App developer? What are the languages and tools one should learn to be a software engineer?

+1 official title doesn't mean anything. at large companies your level might mean something as people know how to pattern match to levels at their company. +1 use software engineer over "developer" on a resume even if it's not your on paper job title as long as it's reasonable to do so and the job duties are analogous to other software engineer jobs. A resume is a tool to communicate your background in seconds to a recruiter or hiring manager. If you misrepresent yourself though it will catch up with you and optimizing your resume is understandably a challenge. It's important though and often needs help from experienced advisors. Codesmith has a head of careers with a "silver tongue" who really works those resumes to tell whatever story you want without explicitly lying. On a background check or a formal curriculum vitae you need to list everything as it is on paper because these tools are intended to be a historical documentation of your background.

Freecodecamp, codecademy, cs50, and Odin Project are good places but anywhere free to get the ball rolling. Then you can get a sense of what your next steps should be. Be it self teaching, a bootcamp, a more formal degree, etc... Colt Steele's Udemy, YouTube, too!