I'm replacing existing third-party applications which have complex JavaScript frameworks with my "in house" apps using HTMX + mostly just HTML+CSS for most pages and functionality. i.e. I'm not introducing a layer, I'm replacing one.

Why not just use html without HTMX you ask? With HTMX I don't have to reload the entire page to navigate, which is especially helpful for making the app responsive even on low bandwidth connections like a bad cell signal.

You said you added a new Go templating layer.

Sorry, I don't follow? I'm just using the templating from Go's standard library. That part replaces existing server-side components of the old applications.

No they didn’t…they replaced whatever backend they had before with a Go server, which simplified things overall.