> If you never seen HTMX it is a small js library that lets you swap some part of your dom with the responses from your webserver.

> This means that in theory you don't need js, nor do your users need to download a full page like it's 1999. Your webserver replies with fully server-renderd HTML but just for the dom node (say a div) that you want to replace.

You got this backwards. With HTMX you need js. But just to swap a div, you can use link target + iframe, like it's 1999.