That’s more than most SWE graduates have done, which is great! But it makes it difficult to judge what you might benefit from based on what you’ve shared.
To answer the title question, the suggestions provided by others here are all good resources for studying algorithms, but no one mentioned Algorithms Illuminated which is of a similar quality. Choose one of these suggested resources that vibes with your learning style.
But don’t discount the suggestions to work on new projects that are outside of your current experience and requires more than your current knowledge base to complete. Trying things you haven’t tried before really is the only way to do things you couldn’t do previously.
Good luck!
You can stop saying if. It is nearly certain that any instance only has a partial dataset in the same way that a search engine only indexes a partial dataset of every web page.
There are bots that were built to do exactly that. I wouldn’t call them bad actors unless the instance owner prohibited such actions.