How to boost my GPA?

I knew of GPAs but I only thought they existed in America, didn't realise my university as well as other universities use GPA as well. My current GPA is a 2.5, I found out a GPA of 2.5 is a c+.

I'm in year one, I know it is just as important as year two and three is but it doesn't count towards final grade. I've been researching postgrad options and I've narrowed down my choices to five universities, four of which requires me achieving a 1st in an undergraduate to get in.

How do I boost my GPA from a 2.5 to a 4.5? I don't know if it's worth mentioning but in August 2023 I got diagnosed with dyslexia, I get DSA but I personally feel I don't get much support. I've been contacting my lecturers and they're not really interested in the dyslexia side, I've contacted disability services and they're slow to respond. I struggle with organisation and concentration. How do I boost my grade so I can do a postgrad?