Is hardware linked between different operating systems installed in same computer?

Is hardware linked between different operating systems installed in same computer?

I know the safest bet If I want to remain anonymous is having 2 separate computers, but I was curious if having 2 OS in different hard drives (both encrypted) but on same computer the same? Is the hardware linked?

Like if I were to use one OS to do sketchy stuff could that be linked to the other OS where I would normal stuff?

Then what is the difference if I have an encrypted virtual machine instead?

I'm more curious about the why of each answer.