Is xquartz still needed?
I am looking for a way to forward X from my Linux clients to my Mac. In the past i used xQuartz for this. Is this still the way to go?
Yes.
There has been no update to the original Apple contributed, open source XQuartz project since Oct. 2016. Whether it will continue to be compatible with current, and future macOS releases is a question mark.
There is no native X support in current releases of macOS and one requires some added X Server implementation for proper display of Linux X based applications served over the network. And with Apple's current apetite for ramping security on macOS, perhaps additional permissions are now required.