The current best option IMO is: Open Full Browser window size canvas (with webgl, webgpu backend graphics ) and draw everyhing yourself ( meaning with something else than the browser layout engine, lots of options available, Flutter, Avalonia etc... ) and deploy with your favourite programming language through WASM.
In fact a next generation browser should bascially be this, with the legacy browser functionality implemented as a WASM module that draws to this single canvas... The browser would become small and much easiert to secure ( only input, audio and general WASI style apis missing and to secure )