I personally recommend LibreWolf over Firefox. It is a fork of Firefox, but it includes some additional settings for better privacy.
Flameshot is a pretty useful screenshot tool that functions similar to the Snip tool on Windows.
If you’re going to be installing apps via Flatpak, I recently learned of an app called Warehouse that allows you to view all the Flatpak apps you installed, the user data associated with each app, and their file location.
If you want another option for LibreOffice, you can try OnlyOffice, but I personally prefer LibreOffice.
If you’re looking for a text editor that’s like Notepad++, I recommend checking out NotepadQQ.
Finally, if you want a notebook app similar to Microsoft OneNote, I’d like to recommend Joplin.