Maple trees have very thin bark.  These cracks were either the result of sunscald or nibbling by critters such as rabbits.  Maple trees may need protection in the winter including fencing to keep out critters and wrapping to prevent further frost cracks.  Sometimes the tree will heal over the cracks. So with this care you are giving it a chance to do so.  See the website for additional specific information.

https://extension.umn.edu/planting-and-growing-guides/protecting-trees-and-shrubs-winter



No.  Paint is not recommended. Latex paint can interfere with healing as the bark expands. It is better for the tree to be exposed and develop its own defensive remaking of the bark.