How to retrieve text only from a post using WP CLI?

Changing fonts and stripping tags can be done with a mySQL query. You’ll just need to figure out the right regexes to search and replace.

For everything else, it sounds like you would be better off updating the single.php template. Social links, ad codes, all those sorts of things are better managed in a single place so that if they ever change, you can update them once and you’re done. You can also more easily segment that part of the code outside of the main content, which ideally is in a <main> tag, so that search engines and assistive technology recognize which parts are templated and what part is the actual unique content of a page.