dashboard is also some kind of magic slippy plastic
There's your trouble. You really need to identify what kind of plastic and use an appropriate activator to get the glue to stick, e.g. https://www.permabond.com/wp-content/uploads/2016/04/POP_TDS.pdf for polypropylene. After that, you can use a regular cyanoacrylate super glue; don't us the rubber toughened one, the brittleness of regular will be your friend when you need to pop the accelerometer off the dash.
Glue only half the area of the bottom of the metal cube and use the curvature to your advantage to leave a gap under the non-glued section into which you can insert an ice scraper when it comes time to pry the two apart.
There's your trouble. You really need to identify what kind of plastic and use an appropriate activator to get the glue to stick, e.g. https://www.permabond.com/wp-content/uploads/2016/04/POP_TDS.pdf for polypropylene. After that, you can use a regular cyanoacrylate super glue; don't us the rubber toughened one, the brittleness of regular will be your friend when you need to pop the accelerometer off the dash.
Glue only half the area of the bottom of the metal cube and use the curvature to your advantage to leave a gap under the non-glued section into which you can insert an ice scraper when it comes time to pry the two apart.