You could do HTMX and WASM, but they both have the same problem in that they generally replace elements in the DOM as opposed to interacting with existing elements in the DOM, and most rendering on both HTMX and WASM actually happens through JavaScript calls.
In either case you’re limited to only interact with the DOM at the level of abstraction that the framework provides through “behind the scenes” JavaScript calls which will always be a subset of the DOM manipulation that is possible by directly using JS. At least, until there’s a standard DOM access API for WASM.
Just as JetBrains is not representative of every dev, neither are LSPs. Some developers want a specialized IDE for their language(s), some want a highly customized editor with their language servers. As long as you efficiently produce code that works, who cares what other people use?