Sign into MS account through local account - hiccups and puzzles, but I'm new to Win 11

I just started up a new Win 11 today (my first, and using factory setup). It would appear that Win 11 forces you to use MS account credentials the first time - correct? I didn't see a choice. Anyway, after going through minimal setup (I skipped and deferred a lot) and getting over the shock of seeing MS default the Documents folders (et al) to OneDrive, I also noticed that it named the Users folder with the first five characters of my MS account email address. The first thing I did was to move the Documents (et al) folders out of OneDrive, which of course moved it to the User folder with the wonky name. BTW, I left the Pictures folder in OneDrive. I chose that configuration because prior to today (and still) I have about 4.5GB of photos there, and almost nothing else in OneDrive, and I want the photos to stay there, but nothing else.

Using tutorials from here (thank you Shawn Brink!), I created a local account, logged out, and when about to log in with the new local account, I saw in the lower left corner the option to log into the machine with either account. BTW, I'll be the only user on this machine. On my current Win 10 laptop, the login screen offers only the local account, BUT - I believe that I never used an MS account to log into this (Win 10) machine. I created the MS acct only to use OneDrive, which was limited. I'm a long-time Dropbox user, and I do backups to a NAS.
So question #1: Is seeing both accounts to choose from at login inescapable because Win 11 forces use of an MS account the first time and if you want to use a local account you'll just accept the two remaining there? It isn't the sight of the 2nd acct that I never plan to use to log into the local machine that I'm as troubled by as the fact that it created duplicate folder structures that I think I'd be wise to leave alone but are definitely clutter! And perhaps troubles that I can't foresee? Or is it normal and fine?

Question #2: Is it safe to assume that as long as I'm logged in as the local user, nothing will be placed in the many MS acct user folders, or do I need to do things to redirect where Windows will send other things? Like say, the Contacts, Links, or Favorites? All 3 of those are new to me.

Question #3: Can I safely delete those many User subfolders under the wonky MS acct User folder? Or most? Both have my OneDrive folder and all subfolders - two is pointless - especially when I never plan to log into the local machine using the MS account credentials.

Thank you,
Mike