Phones, billions of devices running various embedded real-time os, gaming like Xbox and playstation, watches, smart TVs, medical devices, space systems, and many other places are not Linux dominated, and many of these have almost zero Linux presence.
For smartphones, Linux-based Android has the largest market share. It is linux dominated. For less smart phones, there are Linux based operating systems like KaiOS.
Yes, I think most deployed devices don't use Linux, and I'm not aware of any major linux using gaming console, but it's not unheard of, e.g. SNES classic mini. Also, from what I saw, Linux has a good foothold for game streaming offerings, but it's a new market and not yet established that it'll last.