Should my blogs have a summary or tl;dr?

Should my blogs have a summary or tl;dr?

What other things would be good to have on the blog? Like a index or something else? Read time?

Please give me recommendations

Only if it's a skyscraper article. And it's not that important, only you feel like doing it.

And do that at the end of the article, you want to increase their time on your site, they'll just exit the site if the TLDR solves their purpose.