Can you not? It's been a couple years, but I'd written a small 'ical calendar export' functionality on a web project that would prompt to open in ios calendar,

Can you not? It's been a couple years, but I'd written a small 'ical calendar export' functionality on a web project that would prompt to open in ios calendar, and it subscribed to events from the website. That all seemed to work decently enough, and... truth be told, much better than the android behaviour. ios treated the url as something to query (often) which would reflect any schedule updates. Android tied it to your google account (IIRC) and... google decided when to query/check the URL; changes in schedule info on the website would be reflected in an ios calendar generally within a few minutes; android users would see multi-hour, sometimes multi-day delays in updated info.