All of my notes are missing on my iphone

Thank you for the response!

Unfortunately this did not help. The only way I can see my notes have existed at all is if I search for them individually on the Iphone itself by swiping right on the home-screen/menu and typing a relevant word in the title, where they appear next to a Notes-icon like they're in there (figure 1). However nothing really happens when I click on these missing notes, except I am taken to an overview of folders inside Notes (figure 2) where they're still MIA.

But seeing them must mean they're still out there somewhere, right?

To clarify: They are nowhere to be found when searching INSIDE Notes-app and they're also completely non-present in any trash-folder of connected email account that I've found (and I've searched high and low for days).

Here is what it looks like on my phone when searching for one of the missing notes titeled "Möte":

Figure 1

And here is what it looks like inside Notes, where hundreds of notes have disappeared and, as I've previously stated, there is no trash folder (to clarify: the note titeled "Möte" is not among the notes visible):

Figure 2

Where do I turn, would you recommend visiting an Apple Center/Store?

What is the next course of action?

Help is extremely appreciated!

Thank you

Thank you, I will!

Have a great week as well! :)