The way to get better at #HTML & #CSS isn't to build complex web applications with frontend frameworks. The way to get better at HTML & CSS is to write content with HTML & CSS.
Build a blog.
Build a landing page.
Build a report.
Build a portfolio.
Build lists.
Most web applications are simply content + forms in a fancy UI trench coat. 😅 They just tend to be far more "componetized" — making it much harder to grok the underlying semantics at first.