I am probably missing something important here (and have, perhaps, been missing it forever), but I've always just installed myself as the Administrator and only user. Can you brief me on why I might want to have both Administrator and a "daily driver" account?
Oh I have an Administrator account that doesn't have any of my UI / UX enhancements, peripheral drivers etc, it also provides a backup if your main user account gets hosed for whatever reason, you can switch to it and troubleshoot etc.
Generally it's been considered best practice for your general user account to not be an administrator account, but that can become inconvenient.
For migrating / recreating your account it's mostly just important that the new one match the old, so if you've only ever had the one Admin account, they'll both be ID 501, which is fine.
mattspace, I used POP until earlier this year, when I switched to IMAP. So I have tons of emails marked as read (or deleted) in my Mail client that are not necessarily so marked at the host. I fear that they may be downloaded again (tell me if this is a nonsensical notion). Also, I have many hundreds of folders (mostly, but not all, "On My Mac") for clients, projects, user groups, various interests, etc., as well as friends, vendors, colleagues and so on, so I plan on manually moving the ~/Library/Mail folder from one to the other. I'll be doing some research regarding possible problems in manual moving of email data in this situation; if you know of any pitfalls, please let me know.
OK, so I used to keep my mail archive on my Mac, and a whole bunch of my old messages were destroyed by bitrot and Apple's bad mail app updates. I have old messages that are Cronenberged into each other, with munged up headers, and multiple emails in the one message, it's like the end of The Fly.
You can have all those folders etc on the IMAP server. Set them up, then copy the messages up - all the flagging, reply status etc should stick with them. I would honestly do that on the older machine first, get that all done, THEN intrduce that whole new IMAP setup to the new machine. The mailserver is a much safer, more stable place to keep mail, than Apple's filesystem and mail.app's unpredictability.
A really good app for this sort of thing is MailMate - it's a hardcore IMAP client that is WAY more reliable than Apple's app. It gets read unread counts right, message counts right (Apple's app will just refuse to index of see some emails for np good reason). I've used it multiple times to migrate mail between mail hosts etc.
When I set up the 7,1, I used the same user name and password as the 5,1, so my user name and ID number are identical. The 7,1 is current with many apps like Messenger, Contacts, Calendar, etc. I consider Mail to be one of the major items, along with Contacts (the contacts are on the 7,1 but, good-god, I need to go through them!) and iTunes.
iCloud is good for iCloud stuff, and generally works quite well. These newer machines are much better with Airdrop and that sort of thing.
iTunes unfortuately is a dead end - Apple Music is a brittle, garbagefire app in comparison. If you want JUST a music player, check out Doppler, which also has an iOS app and can sync over Wifi directly to your iOS devices. It also watches the folder you tell it your music collection is in, and when you add songs
in finder to that folder, Doppler auto adds them to its library etc.
MP3Tag is a great app for cleaning up the ID3 tags, which are what are probably getting messed up in your case.
If you use Podcasts, Apple is wrecking that in new systems by enforcing that all downloads have to be kept on your boot drive, in randomised folder names, in a location you don't have permission to access directly.
A system I use is Doughnut as a podcatcher, then iMazing to copy files over onto my iOS devices. A lot of my Podcast management involves Hazel workflows to move files from Doughnut's library (which isn't backed up in Time Machine) to a dedicated audio archive, which is.
