synchronizations on all OneNote devices are not working: Error-code: 0x803D0013 bdfno

Hello there, i want to share with you my problem that does not seem to get fixed so easliy. Because after 5 days and by now 15 hours of working, trying and researching, writing with people and supports, nothing helped solving my issue. It seems to be an account wide problem because its the same on all my devices (PC, Tablet and Smartphone).
I've was talking to a microsoft support via chat that had send me over here, because its is the best place to get help exactly for my, as it seems, server/account sided issue. He said that he is unable to look into the server or my account for me, to see if there was the reason for my problem.

But lets start first with details and all that ive done. This is out of my post from "answers.microsoft.com" that I posted over 2 days ago, but nobody was able to help me there:

After 4 days of research and looking through all the FAQs, trying out all the articles ive found with google and spending hours in support chats, nothing helps with my problem.
I'll go into a little more detail below to describe the current situation as thoroughly, precisely and chronologically correctly as possible:
I bought my first tablet 4 days ago (Lenovo Tab P11 Pro Gen2) (Android 13) and have been trying to get OneNote to work since then.
Everything started so far so good, all Microsoft programs ran perfectly on my new tablet: Microsoft 365 and OneDrive. Logging in was also no problem.
But then I wanted to log in to OneNote, but this never worked: Error 0x80070490 always appears.
Various reinstallations of OneNote and a complete reset of the new tablet didn't help either.
Then I found a workaround by automatically logging in to OneNote with my second Microsoft account via the Office Android app while I was already logged in there. This second account is my university account with university ID and Microsoft 365 subscription. I was then able to log in to OneNote with my private account, so that 2 accounts were active in OneNote at the same time on the tablet, but then I noticed the real problem of all of this:
For whatever reason, synchronizations in OneNote only work on my university Microsoft account and not via/on my private Microsoft account, where i want and need to work with OneNote. This was probably the reason why OneNote initially didn't let me log in with this account on the new tablet. Probably the reason for error 0x80070490. So far so bad, but atleast we know the real issue now!
For information in between: my private account has 2 Windows licenses, both of which are still active PCs. Everything works perfectly there, even with OneDrive and so on, that does not seem to be an reason for this whole issue.
So I went looking for clues, as I had never worked with OneNote before in my life and didn't realize that there were apparently fundamental problems with it and the synchronization to my main private account.
I installed OneNote on my Windows PC for the first time in my life and tested it there, but exactly the same thing happened there too:
Synchronizations only work via my secondary Microsoft account and not via my private primary account. For all notebooks on my private account, the following error message appears regarding the failed synchronization:
"OneNote can't synchronize your notes at the moment. We'll keep trying. (Error code: 0x803D0013 bdfno)"
Then I noticed that something seems to be working, because the test notebooks that I created on my tablet and PC on my private account appeared in my OneDrive of the first Microsoft account in the browser (onedrive.live.com) despite the error message. But when I opened them there in the browser with a click, this also worked, but the notebooks are completely empty. Only the notebook and its name have been uploaded to OneDrive, but none of the test content.

And that's the whole situation. I have tried pretty much everything that can be found here and elsewhere on the Internet regarding these or similar problems.
Maybe someone can help me before I completely despair.

I continued testing in the browser  (in various (Chrome and Edge) and in any combination with incognito mode) but I always received the following error: "Unfortunately, your notebooks cannot be retrieved at the moment. Please try again later.
- this issue is gone on its own toady (14th march), i dont know why but OneNote loads now in the browser but still has the same issue as looking into OneDrive: All Testnotebooks created from PC, Smartphone and Tablet are there, BUT all are completely EMPTY!

Because of this and the reason that i get the same errorcode (0x803D0013 bdfnoon) all my 3 devices, there must be a serious error somewhere in the communication between OneNote and OneDrive, on the server or in something bugged in my microsoft account!
But I have no idea which one, how to find it and how to fix it.

I also did the whole thing with my smartphone outside the WLAN via mobile data, both download and the subsequent login attempt to figure out that it might be not worling due to my home network. But still same error.

I have also tried a new user account, but that doesn't help either, no notebooks can be synchronized with the OneDrive there either

Firewall and antivirus program are not the problem either.

WSReset.exe and resetting OneDrive didn't help either.

And all the common things like reinstalling, run as admin and so on i tried plenty of times on all my devices.

I am very depressed and am about to send my new lenovo tablet and simply not use OneNote before my return period for the tablet ends...
I hope there are many people here who can help me fix this problem 🙂 
Thanks in Advance!
Greetings, Alex