It depends on what your goals are.

• Ventoy is good for having an alternate OS on a Thumbdrive. Even with a USB 3 device, you may encounter I/O blocking and find this isn’t suitable as a “daily driver” OS. However,. for booting something like Tails or Windows/Linux for OS specific hardware/applications, it can be a good solution.
• Dualbooting is a good way to “test drive” an alternate OS and also have a way to fallback to the other OS if you regularly need access to some software which only runs on that OS. This is likely to have better performance than the USB/Ventoy setup at the cost of Windows fucking up the bootloader config from time to time.
• Windows/Linux with a Linux/Windows VM is useful when you know what OS you want to run on a day to day basis, but have some reason to reach into the other OS on occasion and aren’t too worried about performance and hardware access in the alternate OS.

Ultimately, it’s going to come down to what you are trying to do and why you want to run multiple Operating Systems. For example, my main system is running Linux. But, I want the ability to run Windows malware in a controlled sandbox (not a euphemism, I work in cybersecurity and lab some stuff for fun). So, I have KVM setup to run Virtual Machines, including Windows.

For another example, prior to making the switch to Linux, I had Windows as my primary OS and booted Linux on a USB stick (not Ventoy, but close enough). This let me gain confidence that I would be able to make the jump.

I don’t have a good example for dual booting. Maybe something like a SteamDeck where you want a stable, functional OS most of the time; but, have some games which will only run in Windows.