I've been doing that for two decades. Most of the spam comes directly to my primary gmail. Because I shared that with friends and family. And at least some of my friends and family shared their entire contact list with the wrong app at least once.

This article however is talking about publishing your email address on a public website. It matches my experience, that simple javascript concatenation stops 100% of spam. Not that I would or ever did trust my primary email address to that.

Years ago, I considered your approach. Programmatically create a custom email address for each person I wanted to talk to.

Then I hit upon a simpler solution. Have one email address. Happily share publicly. And whitelist the sender's email addresses. Emails not in the whitelist go into a quarantine folder that I glance at once in a while.

It's almost equivalent in efficacy, but much simpler to implement.