Looking for suggestions within getting a job in IT or computer science

I have an undergraduate degree in computer science and currently wanting to peruse a masters degree in computer science & mathematics, however when I go to apply for jobs I always end up rejected, even ones put forward to me by the local councils job agencies, I was wondering if people had suggestions on what to include in say a GitHub portfolio, and what to make sure I include within my LinkedIn , currently my GitHub has nothing on it as I much prefer VS code, and my LinkedIn is just previous jobs (fast food, tutor and web dev for a family friend)

Thank you in advance :)