Is it possible to long press on Apple Maps screen in CarPlay and get directions to that location?
As of iOS 14.4, you're not able to long-press a location on Maps in CarPlay to select a destination.
Apart from selecting a destination on your iPhone prior to using CarPlay, you can only select a destination by choosing a previously entered Destination or by using Search.
I often just tell Siri where I want to go and I'm presented with different options that meet my criteria.