I just upgraded KStars to 3.5.3 (says latest stable version, build sometime earlier today) using kubuntu Discover and Ekos/INDI is almost entirely missing from KStars. There is no menu item under Tools, the usual items under Tools>Device Manager are all missing, no EKOS tab in the configure KStars dialog. The only hint that it ever existed is that an INDI toolbar (which defaults to empty) is available.
Richard