This was actually already reported as a bug, and a Community Manager (incorrectly) responded that resizing the display should fix it (it does not), and the bug report was closed without being fixed.
I had to explain to my client how to close the UI so they could play through the prototype. Luckily they were tech savvy.
Yes, you can hide the Figma UI and then copy the link to share, but then the client can’t see the side menu.
