Oh lordy-lord, so much tech-speech, it’s making me go cross-eyed!
( 
I am not built for this. )
I am LUCKY that my main machine here just went and double-Booted since the beginning.
I’ve had Windows 10 on this NVMe for at least 4 years and when I got Fedora 38 (and then reinstalled to get 39 because reasons) on a separate 2tb SSD it just started working.
.
It’s sad that some machines, mainly laptops and old PCs, but even modern PCs, can struggle to “just Dual Boot”, because most times the solution isn’t that simple.
Yes, some most complex stuff is more difficult to multi-boot (like older versions of Windows up to W7, and different Linuxes), but I’d argue that it’s a skill issue on the part of the hardware Devs (and thus those whom make the basic software for them) if they can’t “just dual boot”.
.
As a closure to my minute role in this discussion, SOME old hardware NEEDS to “change the BIOS’ setting for booting” or something (can’t remember off the top of my head right now, it’s something about “the way storage is read”, I don’t have my notes here), so unless I find an easier way to do this (I believe it does exist, the internet just sucks for finding what you NEED) I’d have to jump between those based off if I want to use Linux or Windows XP (Windows 7 happears on both places, but I believe last time I worked on this computer the Windows installs got corrupted, so I have to reinstall them both).