This isn’t intuitive because you can mount anything (mostly) anywhere you want under any path. The whole Linux ecosystem never decided one standard path or mounting method. If you want a disk to be mounted under /home/$USER/Games where /home is also mountpoint to something else, you are free to do so. Desktops automate it and expose UI controls, yet again some apps are from GNOME world, some other from KDE or else and they have different UX and way to expose mounted storage. And I agree it’s not ideal, especially for newcomers.

Oh, and two more random tips:

• commands like df, lsblk or mount can help checking out state of mounted filesystems
• file pickers usually support drag&drop, whether it’s a file or directory that you drop onto it