Quick Questions About WordPress

1. Pages vs. posts? It will just be a "how to" blog, and all posts (or pages) will be the same, except a few keywords changed.
2. Can I have a page work as a directory of other pages, updating every time I release a new page?
3. Can I do "2021" after each title automatically with page posts?

Nice question. Often we think of updating subsequent years with minor changes to make our blog a new one and Google can't understand that we have the same content. If that is so, then you are wrong.

Google regularly updates its algorithm, so you cannot cheat. You have to genuinely update the content with the year.