Hi,
I have also the same problem, and that's really affecting my daily routine. Recently, I realized that my mood is not OK because of the problems I am suffering with my notes.
The app is now is horribly SLOW, I takes huge amount of time to open some notes, specially the annual diaries, which are almost 15MB!
Also, the iPhone getting noticeably warm when I open the app and the battery start draining obvious quickly, that's why I start avoiding to open the app when I'm outside.
All of that happened immediately after I updated the app in Sep 2020, I think, in which the app interface changed. I am really disappointed.
I hope the developers can solve this issue as soon as possible.
Thank you.