Unfortunately if you install Windows from scratch, without going through Bootcamp to install it side by side with MacOS, Hyper-V support is disabled.
This means that I cannot use WSL2. Or Windows, since without a working Linux environment it's useless to me and I don't want to invest in WSL v1. Might as well go for Ubuntu 20.04.
This is the first time I hear of rEFInd.