This is about a blog article from 2018 from a attempt to shrink Qt to work on MCU. But since then, the Qt Company has made a new product called "Qt for MCU" which is not the same product at all. The current "Qt for MCU" is basically a different QML runtime that doesn't really use QtCore and other Qt libraries on the device. I was actually involved in that project.
But I don't know much about its current state because I've now moved to Slint [0], whose architecture is inspired from the Qt for MCU, and which can run on even lower specs, with about 200K of RAM.
The refresh rate on one of those videos seems to be in the 5-10 fps range, but still fairly damn impressive to have crammed Qt in there. UI looks sleek too.
Yes, it is impressive, but that refresh rate is really too slow to be acceptable in this day and age. They should really pick a less demanding style of UI.
But I don't know much about its current state because I've now moved to Slint [0], whose architecture is inspired from the Qt for MCU, and which can run on even lower specs, with about 200K of RAM.
[0] https://slint-ui.com