Adding a .ics file event to Nextcloud/Thunderbird calendar in one click on Debian Gnome or Ubuntu

For a while through some magical happenstance for the first time in my GNU/Linux experience downloading an ical or ics file would open by default in Evolution which would then add it to my calendar in a couple clicks, even though i was not using Evolution for e-mail or honestly the calendar. It was just synched to the same calendar account (provided via NextCloud) that i used for everything else, somehow, wonderfully.

That stopped recently and now opening an event calendar file tries to get me to set up e-mail in Evolution, which i am not doing, i have a 20-odd year history with Thunderbird ever since an Opera bug destroyed much of my mail history.

Current status: still cannot get this basic thing to work.

Saving the file and going to Thunderbird and importing from Thunderbird works, but just opening the file with Thunderbird does not work.

NextCloud is connected as an “Online Account” under settings and i can see all my events in the basic Calendar that comes with Gnome.

This is how the magic once worked but i guess Evolution got more aggressive about setup so i just need something else that will open a .ics file and import it into my calendar account.

OK maybe it’s just this one (malformed?) event that’s causing all this trouble.

BEGIN:VCALENDAR
VERSION:2.0
BEGIN:VEVENT
URL:https://forum.meet.coop/t/sign-up-commons-hour-session-7/978
DTSTART:20220425T130000
DTEND:20220425T130000
SUMMARY:Sign-up commons.hour session

‘cause nothing i have can import it.

It looks like the gnome-calendar app can import events directly, and even Thunderbird now opens an import dialog!

Just this one fails.