Back in 2015 I fixed Chromium's support for server side image maps. It was almost totally broken at the time--any zoom/scale level other than 100% would throw it off, nonzero padding would throw it off, several issues like that. Nobody had noticed because image maps aren't used any more in general, and server-side image maps REALLY aren't used, but I was in the same boat as you: I wanted an easy way out without JavaScript, and I remembered my 90s HTML.

Sadly, after I fixed the Chromium bug, I decided the server-side image map sucked and I wrote the JavaScript anyway. The JavaScript version is better :(