I was clutching at straws: I don’t have an Android device but had seen the other thread and hoped it would help.
On iOS, we see the name of the vault above where the word ‘files’ is in your screenshot, and next to that there is a cog-like icon that leads to settings.
Alternatively, we can swipe down from the top of the Obsidian window to open the command palette. From there it is possible to type ‘settings’ and then open the settings menu.
Does Android offer the same or a similar route?