When you open obsidian, it automatically opens the files that you had opened in the previous session.
This is kind of awkward because I often write some personal notes in the evening, and then I reopen obsidian next to a lot of people, therefore I have to quickly close the notes
It shouldn’t be hard to implement, it would just be an option that would close all the opened files on exit
The Obsidian Homepage plugin allows you to set a page that is always opened at startup. You can also set it to close all other pages, or show a workspace. It might be worth trying out.