I think all the existing answers are on the basis of creating a new Linux VM.
And if I understand you correctly, you already have a bare metal Linux install that you want to run whilst Linux is up.
This is the best search result I could find: https://forums.virtualbox.org/viewtopic.php?t=93437
It sounds like Virtualbox will indeed create a pseudo vhdx that points to a real partition, but windows is going to give you permissions drama.
The above link is out of date though, so its best viewed as info rather than guide.
Good luck.
Funnily enough, I've got a few friends who are long time iPhone users, who actually point this stuff out themselves:
"OMG! Have you seen the eye watering price of the new one?"
"Yay, I finally get stuff you've had for years."
Neither party would ever consider anything else, and they both buy the new model every year. ๐คท
At this point I admit that my reasons for choosing Android all those years ago no longer exist or matter, but I can't imagine changing ecosystem either.