Use a password manager.
https://diogomonica.com/posts/password-security-why-the-horse-battery-staple-is-not-correct/
A very popular password manager among the technocrati is KeePass.
My IT manager says "LastPass for the babies" (implying that its easiest).
edits: link removed due to objections to article's credibility. Direct answer added by request.
As for the question, I'll say it's good (but not great) advice. There's definitely worse passwords out there than 1Iw&iNLy3, and its more of a guideline than an algorithm: while you're using Justin Beiber, I could use quotes from the I Ching, Yogi Barra or Rocky IV, and my 'passwordification' can be more or less complex than yours. So their advice is a perfectly good starting point for folks who decline the use of a password manager.