I am having an similar issue.
config:

{
  			module: "calendar",
  			header: "Agenda",
  			position: "top_left",
  			config: {
				calendars: [
					//{
					//	symbol: "calendar-check",
					//	name: "Thijs",
					//	url: "https://calendar.google.com/calendar/ical/*******/public/basic.ics"
                   //  },
				     {						
						symbol: "calendar",
						name: "Andrea",
						url: "https://calendar.google.com/calendar/ical/********/public/basic.ics"
					 }
				]
			}
		},

Logs show:

[2020-12-26 13:24:33.391] [INFO]   Calendar-Fetcher: Broadcasting 10 events.
[2020-12-26 13:25:03.322] [LOG]    Use existing calendar fetcher for url: https://calendar.google.com/calendar/ical/*****/public/basic.ics
[2020-12-26 13:25:03.324] [INFO]   Calendar-Fetcher: Broadcasting 10 events.

Some fun details:

• the first ical (now with the //) does work and gives a correct feedback. The second ical is from the same workspace, has the same settings for publications. As far as my knowledge goes the log even shows it fetches 10 events. And I can wget the ics files but still I get a ’ no upcomming events.’ message.

So @jonspraggins; did you find a solution that could help me into the right direction?