Notes going blank (not just appearing blank, contents are totally deleted)

Device: Ipad Air 4th (2020)

2 months ago, A problem appeared that my notes take some time to show its contents. I thought it's just a performance problem as I was mostly activating battery saver and the weather was hot that my Ipad was getting a little bit hot. 3 weeks ago the problem started getting into a new level of furstration, after writing or editing notes, sometimes these edits are instantly deleted just as I get out of that note or the notes app, if it was a new note, all the contents are permanently deleted and even the auto title is returned back to "New Note".

Have any of you met this problem before?