There is a built-in feature, known as Application Guard, on Windows 10/11 that gives you exactly this out of the box, with minimal configuration. Biggest downside is that it only works with Edge.
This seems to be an artifical limitation in Windows Sandbox, as WSL2 and Edge Application Guard both use separate VMs and you can run them all at once.
"Krypton" is the name of the isolated microVMs in Hyper-V, but they don't really document it at all.