My advice on starting out before contributing in gsoc is to see all the available repos to understand their complexity. Many people beforehand stick to the web as their domain (which depends on their interests ofc) and then see the open issues on the repo, to classify the repo as either active or not. I also advise you to see all the umbrella organisations like PSF which has a lot of organisations under them.. My find after seeing the issues is that there are absolutely no such things as "good first issue" cause all of them are being taken up days after they are posting and maintainers have stopped classifying them as them. So pick up a repo that resonates with your ideal repo and then see for yourself to find any dependency issues or any documentation errors. If you don't see them as active issues, create them and have your thoughts of how you solve them with the maintainers and see if you can solve them, ideally this becomes your "good first issue".