Here’s a shortcut that lets you select (today’s) calendar events and adds them to the Logseq journal page. Tested only on MacOS, but should work fine in iOS.
Note: this is not a sync, and it only gets today’s events. There is also the agenda plugin with much more options, but i did not want to make my calendars public.
towards the end of the shortcut, you can edit the template and add the end date. Just Right-click in the text field and “choose variable” → “SelectedEvents” → Pick “End Date”