Rocket car that goes through solid matter.

Time machine, please

Holodeck

Iron Man suit.

basically a better newer Kinect for my kids. something that'd let them dance or play or see themselves in the game without a controller

robot butler that does all my chores

This is really specific. But I have wanted it for years. A switch for two 3.5 mm sound. Basically plug two inputs into the box, have 1 output and a simple physical switch that would let me flip back and forth.

Something extremely modular and upgradable like the Framework, but with a 4K 120Hz HDR OLED display, that can fold back into 2-in-1 mode and that has connectivity for full bandwidth of an external GPU. Additionally, some way to connect to up to 3 displays at full 48Gbps HDMI 2.1 bandwidth (each) - at least - DP 2.1 would be even better. Maybe via multiple display outputs or some insanely-high-bandwidth port like Thunderbolt 5 for dock connectivity.

The intent is to basically have a tablet-to-laptop-to-desktop experience, with virtually no compromises.