Hi Timo,
Among the buttons below an entry, "Add tags" for regular tags is my most used function. I don't use "Add people" nor "Add tracker". I think even for people who do use "Add people" or "Add tracker", they still use "Add tags" more since regular tags is a more useful way of classifying an entry (ex. Work, Vacation, Hobby). Maybe you could verify which among regular tags, people or tracker is the most used tag among Diarium users.
It makes sense to simplify the most used function. Every time I want to add a regular tag, I have to select "Add tags" twice. I'd rather click once since I use "Add tags" 99% of the time.
Suggestion:
Move Add people and Add tracker submenu to a different button, such as Add rating.
Make 8 buttons instead of 6 so each function has its own button.
Combine Add photo, Add audio and Add file buttons, then breakdown Add tags, Add people and Add tracker.

Thanks!
Diarium version: 3.0.87
OS + version: Android
Device model: Xiaomi phone