The difference between structured content and semantic HTML is that structured content is information designed for any interface. They are legible to algorithms which will take these content packages and turn them into a page on the web that will be one source out of the many that you describe in the search bar. Semantic HTML can be described as the syntax used in order to create the information that will be exposed on a website. Another way to think about it is the skeleton of a website.
Structured content and semantic HTML work together by communicating information visually to its readers and to it's algorithms.
It's important to have both structured content and semantic HTML on webpages because it makes viewing and accessing content more readily available and easier to understand.
In Denise Jacobs article, I think the most effective method to get rid of my inner critic would be to switch it up. I think trying to find other methods to accomplish my goals and squash those feelings of imposter syndrome by trying my best to be proactive will eventually make me realize that I have learned assets and I've put in the effort that is expected of me.
David McRaney describes hyperbolic discounting as a process of becoming more logical when one is forced to wait due to the later payout becoming less and less worth it over time. I think a solution he mentions that would help me is to imagine the future me rather than the current me. It feels nice to procrastinate work in the now, but the future me will become swamped with work and will be cursing past me for not touching it until the last second. Instead, I should do my future self a favor and try to counteract procrastination.