Can't create a New Note on my Android Cell

[Marnette 10]

I have an Android Note 20 Ultra, and when I try to create a new note, it doesn't get added, nor does a Notebook selection come up.  In fact, my main Notebook (of 30,200 Notes) is critical to me at this time for a large research project that I am actively working on.  It isn't even listed in the Notebook lists.  All the others are.