I'll answer what I can in good conscience.

Is that a good idea?

If you keep in mind that it won't 100 % behave like a "proper" installation when things go weird it's fine.

Do different distributions work better or worse on VMs?

VirtualBox comes with some pre-made profile for some distributions but I've never been able to tell what those actually do, other than by default selecting virtual hardware that is supported.

Are there any major differences when using linux in a VM compared to a bare metal installation?

VM "hardware" is well supported, but anything requiring proper hardware acceleration (of any kind) will either perform terribly or fall back to a software-based backend. I.e. desktop compositing or hardware video decoding may or may not work as well as a native installation. Video games likely won't work in a usable way at all, unless it's Solitaire. Also the hard disks are decoupled from the VM to the host system and you need to manually forward USB devices to the VM or the system might not be able to detect them.

Is there any [dis]advantage to “Linux VM on Windows” VS “Windows VM on Linux”?

That entirely depends on what you want to use both systems for. If you already have Windows installed then I'd like to suggest the following path:

• run some live USB to figure out whether your hardware is supported (graphics, sound, network, printers - especially the latter two)
• if so, install Linux in a VM first (install multiple desktops and try them out, because why not)
• figure out what programs are available that do the things that you usually do on Windows - keep in mind that just because $PROGRAM is written by GNOME/KDE/LXQT/... people that doesn't mean that it won't run perfectly fine on other desktops. Also: distributions may not ship all software, don't forget to check Flatpak/Flathub if your distribution is missing some software.
• try them out in the VM to see if they meet your basic requirements
• install the Windows version of those programs on Windows
• over time, replace the Windows programs that you used to use for the ones that are also available on Linux
• if after a few months there are no non-Linux programs left: Congrats, back up your data and just use Linux
• otherwise: figure out whether the programs that you need will run well enough with Wine or in a Windows-VM

If it turns out that there's just too much Windows-only software that you can't part with then you can just delete the VM and that's it. On the flip side you can find software that may just happen to be better than what you used previously. Also trying out various distributions is much, much easier this way - installing the tenth distribution on bare metal because you weren't happy with the previous nine isn't particularly fun.