I have my Exchange Online calendar synced with my iPhone (most of my business appointments are saved in Outlook calendar). They show up well in the calendar app, I do get notifications and reminders (also on my apple watch) but when I use the new calendar widget in ios14 i see "no more events today" message.
But when I go inside the app (expand the widget, everything is there). I have the widget set to mirror my calendar app (all calendars). I tried different settings but no events show up in the widget.
This has not been solved by updating to ios14 beta 2.