[flohofwoe]

Calling between WASM and JS really hasn't been slow in browsers since around 2018:

https://hacks.mozilla.org/2018/10/calls-between-javascript-a...

It would be extremely surprising if calling overhead into JS to manipulate the DOM is noticeable in profiling instead of being dominated by the actual DOM manipulation (I have mainly experience with WebGL and WebGPU, where each call also goes through a JS shim, with a sometimes nontrivial amount of work happening in the JS shim, and the actual call overhead from WASM into JS is absolutely negligable compared to the overall cost, which is typically inside the WebGL and WebGPU implementation).

Also: if performance matters, don't use the DOM in the first place!