Don't get too worked up about the upkeep for frozen paint. It isn't as bad as people make it to be. For me I'm picking up my frozen dark silver M8C GC this weekend. I ordered Dr Beasley products as it has great reviews for quality for matte paints
https://www.drbeasleys.com
After extensive research, I ordered the Matte body wash for washing the car, Matte paint coating for hydrophobicity, and Matte final finish for cleaning touch ups and contamination in between washes.