For testing purposes the display is able to run with 3.3V, all power and logic pins driven by a 3.3V microcontroller. The controller does not supply enough current / power for regular operation, the brightness of the LED row is not stable when the number of pixels change, and the maximum brightness cannot be reached.
Floating data / input pins appear to have no defined state, the display might show random pixels changing their state.
The unit has a 2.5mm pin spacing it fits into a breadboard just fine with some (unconventional) force applied.