MS by default uses local time on the HW / Cmos clock. Change this in registry for dual boot. Doesn't seem to matter with a VM.
Everything else uses UTC on the HW / Cmos clock and uses the regional settings for the user to display local time.
Ihe free VM (Windows and Linux both use Oracle) and typical RAM means the clunky Dual boot is history. I last used it in 2016 and after MS ditched the older NT ini file for boot and PCs had UEFI boot, you needed to use GRUB om Linux. That worked up to Dec 2016.
If you have 8G RAM or more you don't need dual boot, except unless you have hardware the VM can't access. Better to put MS in a VM on Linux and only have Calibre on Linux. You need a VM ANYWAY, often on Win10 or W11 for reliable running of 32 bit SW and most Windows programs not updated since Vista. That's why MS includes Vbox on Win 10.
MS updates can simply stop ANY booting occurring and may stop you shutting down windows or slow starting up, so Windows on a VM is better.
If you have Win7 or earlier (even on a UEFI bios) booting in legacy mode there is an MS application to convert that install into a file for Vbox VM on Win10. The file works on Vbox on Linux, though not with default creation settings.
I've saved my 2002 XP laptop and a Win7 install using legacy boot on a UEFI tower to vm files on Linux with this free MS Utility.
https://learn.microsoft.com/en-us/sy...loads/disk2vhd
I used a USB HDD as the destination. You can install the files in a Vbox install on internal drive or ext4 USB HDD on Linux, back up the saved stated with rsync and restore on a different Linux laptop. Unlike dual boot, XP takes a few seconds to load, win 7 a bit longer and Win10 40s on Linux, and map linux USB devices (direct), directories, linux serial & parallel ports, graphics, network, sound to VM devices. Copy/paste data between a Linux window and Windows, drag & drop files.
I recommend Mint + Mate + X for best reliability & performance, but with Linux you can install multiple desktop systems and choose at log in.