What I would suggest, is try to use BTEC as a stepping stone for uni. You might find that sometimes you don't need to work very hard to achieve decent grades, however, use your time to master exam techniques and how to write essays! It will help you so much in uni and you won't struggle that much in the first year. I'm doing BTEC myself in Computing Ext L3 and my predicted grades are D*D*D*. For my coursework, I used Google Scholar and Sci-Hub, I highly suggest using them. Don't use information from the normal internet/websites since is not a good practice. Also, please do the references in your essays because if you copy something from the internet or research paper and you didn't reference the author it will be plagiarism! I suggest using Chicago style reference. Try to write between 4k-8k words and revise for exams earlier. Additionally, try to get job experience in a related field, It will massively boost your uni or apprenticeship application.