That's effectively the same as my last sentence.

For a dual boot configuration, you might as well not copy anything over. You'd be better off mounting the Windows partition in the Linux install. There's not a great reason to dual-boot for non-technical users, though. The point is to end up on a system that works for them, not to have one that works for them and a derelict system that they don't know how to remove, and that can destroy their dual-boot setup if MS decides to push an update that overwrites the boot loader, leaving them unable to access the Linux install.

It's not just shrinking and copying over to the new `/home` because of the locality of the data. If your NTFS partition is taking the entirety of the disk (minus EFI and system partitions), shrinking it will then make it take up the first X% of the disk. Then you have to make the linux installation on the last (100-X)% of the disk, copy the files over, and then when you delete the NTFS partition, your Linux filesystem is on the last half of the disk with a big blank unallocated area on the beginning. BTRFS or LVM2 could help a little bit there, but that's far from ideal in any case.

Probably the best approach would be to shrink NTFS, create a new partition at the end of at least the right size, copy the files over, then wipe the NTFS partition, install Linux as the first partition (after system/EFI and such), then copy the files into the user's home, and then remove the documents partition. That's still not super reliable, though. You are at the mercy of your documents sizes, filesystem fragmentation (remember, even if your filesystem is mostly empty, you might not be able to shrink if fragmentation is in a bad place. You could defrag, but then the install time can balloon up many hours for the defrag process alone, just to shrink a filesystem that you're going to delete anyway), how big the Linux install will end up being, and many other factors. You'd have a lot of people who simply can't copy their documents over on install who will be simply SOL. I can't think of a situation where this kind of thing wouldn't be better served by just telling the user to backup their documents to a USB drive and move them back afterward, because many people are going to have to do that anyway.

Linux has to install somewhere, and it needs a filesystem that supports POSIX permissions, so you need a partition formatted for it. If NTFS is taking up the entire drive and can't be shrunk, where does Linux install?

You can't do this all on the same drive, because you need a place to copy the documents directory to. You need to delete the NTFS partition to create the place to copy the files to, but by the time you've done that, the Documents are inaccessible. You could do it in memory, feasibly, if you create a RAMdisk and are lucky enough to have enough memory for all your documents, but then you're still gambling on not running out of memory during the install.

So it is possible to copy the documents on the same device, and it's possible to even automate the process, but it's not possible to do it reliably or safely, and the reliability is so low that it's not worth even offering the possibility. If somebody has a handful of gigabytes of documents, it's already a nonstarter. To be safe you'd demand the user make a backup onto another device anyway, in which case they might as well do that and then copy the files into a fresh install themselves

I have tried a few times and only had bad trips. Not only that, but I used weed regularly beforehand, and alcohol occasionally, and after my last mushroom trip, both reliably give me anxiety or panic attacks every single time I use them. The first time I used weed after the mushrooms, I had a panic attack so bad I ended up calling 911 because I was convinced I was going to die. It's been two years now, and the last time I tried weed was three months ago (a CBD heavy strain; I had 10mg CBD and 2mg THC), and the last time I tried alcohol was a month ago, and both times gave me an anxiety attack.

Maybe I'll go back to normal eventually, or maybe I had a latent anxiety disorder that was triggered by the mushrooms and I'll just never be able to enjoy weed again. I don't know. My friends didn't have experiences as bad as mine, but they did have a bad time. Most of my friends love psychadelics, and I'd never take them away from them, but before we all tried them, they were talking the same way, and it's what made me excited to try them. I wasn't expecting it to do to me what it did.

I had a similar experience on a very small dose of magic mushrooms. Significantly smaller than necessary to even have hallucinations (under 1g of dried magic mushrooms). I was filled with dread and terror and felt like I was going to die. I was told by my shrooming friend that it was probably just bad, and to take some of his good stuff. I took 1g, and again had hours of terror and dread, and thought I was going to die for several hours on end. I then had nearly constant anxiety for about a month afterward.

I think many pro-psychedelic and pro-drug people in general underestimate how much these drugs vary with people. I have a friend who will make a gram of weed into cannabutter and eat the whole thing in 1 sitting, getting about 200mg of THC at once, and not have any major problems. He was a big proponent of "there's no such thing as too much" until he saw another friend of ours have an incredibly intense panic attack on 10mg of THC. My wife has intense anxiety on as little as 2.5mg of THC, regardless of CBD and CBG levels (whether via gummies or straight plant matter); no dose can be thereputic for her.

Based on the number of people I know who have experimented with these drugs, I think there's a smokescreen effect where people who have bad experiences don't talk about it nearly as much as people who have good experiences, so it seems significantly less risky than it is. Of the 10 or so people I know personally who had a psychedelic experience, about a third of them have had bad ones. They just don't really talk about it and never want to try it again. I wouldn't say that most people should try psychedelics at least once unless I knew what the actual numbers were, otherwise I'm pushing many people into having a horrible nightmare for hours on end.