Standalone calendar + contacts via Radicale on a NAS, syncing to iOS Calendar / Contacts over CalDAV and CardDAV (without iCloud)
You’ve spent enough years watching iCloud quietly rewrite your contact data, randomly de-syncing one device, “merging” the same family member into three different cards. The fix is leaving iCloud and running your own CalDAV/CardDAV server. Apple’s Calendar and Contacts apps …