The phone refuses a lot of the times to search local files that I know are in the phone

Hello, honorable society

I have a fairphone 3 since 2021 and I am very happy with it. Except that I often store PDF I make myself with useful websites on them so I can use them anywhere.
Since around a year , more or less, the search menu for looking for local files, refuses to find files , but not allways. But sometimes it will refuse for as long as I try.
It shows instead a hourglass with red sand inside and it says “impossible de charger le contenu pour le moment” which means "impossible to load the content (or data) for now.°
The files are there but since I have them in directories that are themselves in directories, it is faster if I search the files I need by their titles with the search by words in a space. I am not mistaking of space of search. I know there is a space for the card that is added to the phone and a space for the local phone’s memory itself. I am not mistaking of space , and I am not mistaking of orthograph when searching what I look for. Is there a reason for it not working? What is the procedure?
Also, I am sorry , I cannot put screen shots. It is the first time I write in this forum and I can’t find a menu to add screenshots.

Thank you very much for reading.

Unfortunately FP3 is quite short of RAM. Have you tried going to Settings > Developer options > Running services for a truly accurate account?