You should be able to do that with a game engine like construct https://www.construct.net/en , phaser or godot. That’s pretty easy even for beginners
Any flatfile cms should do the job.
You could try https://automad.org/ and setup up a password page to keep it private. It’s super simple to maintain and secure. You just need a vps and a domain.
And ban your speaker MAC if you use it to playback with the same account