Personally, as you may have read, HTML is completely uninteresting to me at the moment. I bash it a lot.
You're asking about hands on work and projects to use your HTML and CSS knowledge in. Obviously, I can't list any specific examples, but I would just try coming up with a specific things you would like to do that are very simple and research how to do them via youtube of stackoverflow. This may not be helpful lol, but learning other scripting languages may help you put the HTML into proportion.
I don't have an answer for this but it's my favorite question because this is exactly how I feel about it lol.
I've heard that Build an Interactive Website is a really beginner course, but I'm not sure. I would say yes though, just because the course is sunsetting sometime in the future so I would take it if I were you.
I guess I really just suggest looking into JQuery and SQL and Angular JS, stuff like that. I know SQL has nothing to really do with it, but I feel like the more languages you learn, the more you see how they work with one another. When taking python or JS, you can be like "oh this is really easy because I'm just building simple things", but in real life these languages work with other one's to generate massive interactive websites, computers, and other huge things. Programming is really overwhelming sometimes, and codecademy does a good job of breaking it down to seem simple, but I also know that this website is really to stimulate people and help individuals discover whether or not they have the aptitude for programming or not. If computer science is something you want to do for an actual career, you really have to dig deeper, so even though this can be hard, sometimes stone cold research is the best thing you can do. You need to have questions to look up, and you also need to have a goal or project that you have in mind so you're not just aimlessly collecting information that overwhelms you. Personally, I'm taking an AP Computer Science class in school, (which you know), which has really put everything into perspective and helped me to piece things together more. I obviously realize that not everybody has this opportunity, so what I suggest is looking to other websites for research as well as coding experience. The best way to gain experience is by actually making something, which is SO hard, but you have to have an idea first.
Another cool thing to do is ask somebody who has more experience than you to kind of collab with you and teach you things that you didn't know. The reason this can be helpful is because you can see somebody else's processes, and they can piece things together for you so you're not overwhelmed and confused not knowing what your next step is.
Again, I'm going to say that I have absolutely no experience in HTML, but I do know that using programming in a practical sense is really hard. I wouldn't have responded if I didn't know you either lol.
But I know you are somebody who really loves helping people and you love to learn, so I think you really should do the best you can to get as much knowledge from here as you can, and then extend your scope to other resources.
Anyways, this is really long, and probably extremely unhelpful, but I hope that you at least get some inspiration out of it.
You've got this! :))))
edit: I tried to find typos, and goodness gracious there were so many I'm sorry