Swissvax has a line of products to care for matte/frozen paint finishes
I've used their products in the past and liked them a lot (still use their leather
cleaning/conditioning products) , have switched to Zaino since (they don't have a frozen/matte product)
But basically just be careful in not using products which are using fillers/wax etc
Frozen paint requires actually less maintenance than "gloss" paint and you have the
benefit of frozen paint "hiding" swirl marks and marring quite well
There're a couple of other interesting pointers for you.