What you think about the module vs what the module actually does seems to be two different things.
I’m telling you that, based on the documentation anyway, the Tuya component enables these things ( https://www.home-assistant.io/components/#search/tuya ) in Home Assistant. It’s possible that it does more than the documentation suggests… that happens some times. But… it’s unlikely. It’s also possible that it is sending events through to Home Assistant. That would also be undocumented, if it did. However, if it did, they don’t just “pop-up”. Events would have to be detected using an automation and acted on. The only things that “pop-up” in home assistant that I’m aware of are persistent notifications. Again, it’s possible that the Tuya component is supposed to do this. But, if it did, it would be vastly different than any other component, and 100% undocumented.
From what I can see, the Tuya component does not do what you think it does. That doesn’t mean it won’t do it in the future… the platform is still new and the developer has added new features and device types since it’s first release. But as of right now, I’m not seeing anything that suggests motion sensors are supported in any way, and I really doubt that if/when they ever are, anything will “pop-up” in Home Assistant as a result, unless you write automations to make them “pop-up”.