Or do not reorganize the folders at all, and learn how to organize your images with keywords, collections and smart collections.
No Johan, you and I have had this argument and I vehemently disagree.
That would be a big mistake and a violation of every computer file organization principal known to mankind.
It is madness not to have a good organizational folder and file name structure on your main data disk or location.
You can't just blow off a good folder structure and use LR to sort everything just because you can in that one program.
I spend a lot of time on key words, and they are important for many reasons, not just because LR can use them to sort a relational database and create collections. Collections are great, but that is not a good reason to abandon all sensible computer organizational basics.
I think in their enthusiasm for LR and its amazing collection powers, some gurus go over the top and keep saying you don't need a folder structure with your photography at all because you can just sort whatever you want from one massive pile of goo using key words. Huge mistake, and I think gurus have done a lot of damage teaching that bad practice to novices and new LR users and photographers. That is what they told me so many years ago, and I knew it was wrong, so I ignored that advice. But I did listen to them on Key Words and since Day One w LR I have always worked hard in post to assign good key words to every raw file.
I bet I could find a bazillion pro photographers who would disagree with your take on not needing a sound folder structure if we ran a poll.
Not having as good folder structure in your work is a terrible idea for 45 other reasons that go beyond LR.
Do both. Have a sound organizational structure to your data disk and also always use good key words, titles, captions, file names and metadata in your post processing. Key Words are supremely important. That I agree.
But the OP already has an organizational mess with data spread all over several disks with senseless folder names that he probably let some program or device name for him, and he is thus confused about what he has and wants to clean it up.
Let's not advise him to create a big steaming pile of mess (like he has now and is trying to fix) on his new big 16 TB data disk. If it were up to some of you gurus, he could just dump 250,000 raw files with their random file names and thousands of badly named folders into the new disk and just run collections from here on out (if by some miracle he had good key words assigned to them all). No. Please no.
He needs a good organizational structure on his new master data disk.
Concerning Victoria's response, yes, I agree that he could move the files first and relink to the cat, then do the organizational restructuring from within LR as he tools his organization and folder/file naming conventions on that new 116 TB HDD. I said that on my first post. I was just offering a conceptual alternative using the sidecar files because he had such a mess that trying to move it all and relink it could be a bit of a tickle.
But Victoria, you said it would be easy to move all those files to the new disk and then relink them all to the cat. Maybe if you were doing it, but if it were me or the OP, maybe not so smooth. LOL