No install, ever. https://cncfoam.com runs entirely in your browser using WebGL for the 3D view and WebSerial/WebSockets for streaming — there is nothing to download and nothing Windows-only.
You also do not need an account to do the important things: simulate a cut, download G-code, stream over USB or Wi-Fi, and browse the shape library are all free and anonymous. An account only unlocks things that need an identity attached: saving named projects to the cloud, publishing shapes to the public library, posting here in the help center, and liking or commenting. Create one in about thirty seconds if you want those, otherwise just start cutting.
You also do not need an account to do the important things: simulate a cut, download G-code, stream over USB or Wi-Fi, and browse the shape library are all free and anonymous. An account only unlocks things that need an identity attached: saving named projects to the cloud, publishing shapes to the public library, posting here in the help center, and liking or commenting. Create one in about thirty seconds if you want those, otherwise just start cutting.