If you can compile your lisp to webassembly it will run in the browser

Have you tried Firefokth?

https://www.gnu.org/software/emacs/manual/html_mono/eww.html

1 Overview

EWW, the Emacs Web Wowser, is a web browser for GNU Emacs that provides a simple, no-frills experience that focuses on readability. It loads, parses, and displays web pages using shr.el. It can display images inline, if Emacs was built with image support, but there is no support for CSS or JavaScript.

To use EWW, you need to use an Emacs built with libxml2 support.

back in the early days with the tag it was possible to run stuff other than javascript on client side (perl for instance)

i believe lisp should've been also possible..?

If you want to write frontend code with a functional programming language, Elixir may be worth your time.

I mean writing a JavaScript LISP interpreter is rather trivial...

Not sure what you mean exactly. JavaScript, for better or worse, is sort of essential to the modern web. You could write things in Clojurescript, but that still compiles down to js.

There is Nyxt which is written and extensible with Common Lisp.

If no then why nobody has made it already?