Difficult to predict in advance.
Though, if each OS is installed on a separate disk, then any difficulties should be minimal – this is usually the safest scenario.
While it’s difficult to predict absolutely how Windows (10/11?) will react, experience has shown that it’s likely to recover well enough after adjusting to the new system hardware, and a few reboots.
I might loosely suggest the following procedure:
1. Disconnect the Manjaro disk temporarily and connect the Windows disk to the desired port. Make sure Windows is functioning as it should be.
2. Re-connect the Manjaro disk to the other port - boot directly to BIOS and make sure the Manjaro disk is detected and that Manjaro’s UEFI/Grub is first in boot order.
3. Reboot.
All being well, you will boot to the Grub menu and see both Manjaro and Windows as available options – boot to Manjaro first, just to double check everything is still working (Linux is rather resilient, so I expect there will be no major issues).
My personal recommendation – Avoid sharing Steam games on a Windows NTFS files system, if possible; instead, move them to a native Linux file system. I understant this isn’t always convenient, or possible due to space constraints, but doing so can potentially help avoid complication later.
Some time ago I authored the following tutorial, which I link here not for you to follow now, but in case you might find any of the content useful for reference.
Regards.
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