You want "Save to my calendar" but we still don't have full support for date inputs. Chrome has supported the main features since 2012, Firefox joined only in 2017, and we're still waiting on Safari to make a move.
Well, I wanted "Save to my calendar" when our self-built date inputs still opened new windows with html tables as calendars to pick a date, but I get your point and I lumped this under "forms suck". I still shudder when thinking about implementing multi-file uploads in php.
I have an application that is partially broken in Safari only because of the lack of support for input type="datetime-local". Very frustrating.