What is one tech product you still can’t comprehend how it’s built?

Google maps? What don't you comprehend about that? Do you remember tripquest and MapQuest back in the day? Modern Google maps is just dynamically loading series of images. An Atlas of images really. A MIP MAP, To make a pun. Those images are associated with coordinates. Get GPS data from user and link it with image and you have where you are. Everything is just linked database information on top of that to provide richness. Stores, location data, parks, etc. Layers and connections.

MRI and similar scanners

Professional simulation software with finite element methods and the like

The backend of all sorts of networked systems (internet, phone, banking, booking, satellites)

Asteroid/orbital trajectory prediction suites

Relativistic simulations

Multiplayer synchronization and tricks

I know how it works but CPUs. How they’re built seems like some wizard shit.

Integrated circuits, especially modern computer processors are extremely complex

Palantir/Foundry

SolidWorks.

ASML TWINSCAN NXE:3600D

Accelerometers

Second Life