Browser sandboxing is more battle tested, and probably a lot more researched, and with more fuzzing performed on it.
I know that at least X11 is not sandboxed with snap/flatpak/etc., and there is no sandbox for macOS/Windows Zoom client, so using web client is infinitely more isolated.
Browser vendors push sandboxing technology and everything else kinda follows behind by years. It's unlikely you'll find a more powerful sandboxing approach than what's in Chrome.
