As I understand it, imminent macOS release 10.15 will require all apps are "notarized" in order to be installed.

Is KStars/Ekos for Mac currently notarised or plans to make it notarized (or are there ways round it)?

I'm uncertain what notarization involves and to me it sounds like a retrograde step. There are rumours that the requirement might be slipping and wont be introduced immediately on 10.15 release but I've no idea as to the reliability of these rumours.