Disclaimer, I am in no way affiliated with brilliant.org but am a happy user. Do yourself a favor and invest in a brilliant.org membership (there should be a trial period, but tell yourself if you like it and stick with it you’ll consider buying the lifetime membership). Then do all the Logic Courses. You could work your way through their Computer Science stuff after that. They are actually pretty fun and making mistakes is all part of the process and viewing the answers will often correct what you missed. The way it works is you are given multiple choice or fill in the blank questions usually with only one right answer. The problem statements are very exact and taking in all the relevant information is necessary. Then you kind of have to deduce for yourself the answers. Brilliant.org is literally the best investment I’ve ever made to increase my mathematical ability second only to University where I took up to discrete math. I would definitely do the trial period though because it may not be for everyone. I have mostly used it to review material that I basically should already know so I don’t know how difficult it would be for someone approaching it at a perspective of not knowing much about the subjects. But, Brilliant setups up prerequisites for each course so you should know atleast what you could work on before certain ones. Best of luck and I hope someone tries it after this recommendation because I truly do love the platform.