an alternative for the notes app for diary

Cannot get native notes app to work in multitasking, if I use it in split view or having the notes app floating, it will not work as background, or maybe this is the a´other way around. If I use SlideOver view, the only thing I have noticed actually working. If I have the notes app open and then add another app in slideover, the notes app works as expected. If I do it the other way around, I cannot seem to get to edit the notes. In split view this doesnot work at all. Please help.
All of this means that I cannot use this app as a diary so I need another alternative for this app because I write diary every day.
I regret that if I use something else I won’t access all of the 800 notes I already have, because I refuse to go and move them all.