Run browser and/or mpv directly on hardware?

Context: https://www.youtube.com/watch?v=QKzRf8B-oDk

Would it be possible to run mpv and a browser directly on hardware somehow? Perhaps in an environment that doesn't classify as an operating system according to the definition in those California codes?

I know that an operating system distributes workloads and facilitates communication between various hardware components, but would it be possible to build a Linux kernel that is "only" an interface to the CPU, a GPU, a sound card and a keyboard? One that can take commands to run for instance a browser^[Nowadays, a browser feels like a container that can run most things a physical computer would: stream media, serve as a word processor, play simple games, what have you.] and mpv? Having the user manually - through commands of physical switches - handle the inter component communication? Or perhaps by being a kernel it already falls under the definition of an OS?

I'm just spitballing here. Barely know what I'm talking about, so please enlighten me! :D