Why would you not want to be using a rendering library? Your code is basically storing your application state in the dom which will turn into a horrible mess as soon as you reach any actual level of complexity. I know first hand. I'm traumatized from having to maintain large jquery code bases in the 00s. No serious professional writes code like this anymore.

Also, your vanilla code isn't modern. It should look more like this:

document.querySelector("#element").classList.toggle("hidden")

I could see not wanting to use a rendering library if you're building a simple site on top of basic static HTML, but that's not a serious discussion for industry professionals, and even still, jQuery is such a heavy dependency for saving some characters. If you find yourself using it so much you need the extra convenience then your site is already complicated enough that you should be using a rendering library with state management instead.