I get a work e-mail with an calendar invitation and accept it. It is stored in my private calendar instead of the work calendar.
Calendars in Thunderbird's lightning allow the selection of an e-mail address. Invitations to that e-mail address are stored in that calendar.
I used the "provider for google calendar" addon for thunderbird: https://addons.thunderbird.net/de/thunderbird/addon/provider-for-google-calendar/. It does not support selecting the e-mail address.
But google has proper caldav support, so you do not need that plugin anymore.
Lightning only supports "calendar collection" URLs, but not "principal collection" URLs. A calendar collection is one single calendar, a principal collection is a list of all available resources, i.e. calendars.
I have a work account at gmail, and 20+ colleagues whose calendars I have. I do not want to add each of those calendars manually.
TbSync addon for thunderbird: https://addons.thunderbird.net/en-US/thunderbird/addon/tbsync/
It supports principal collections, and I can comforably choose which calendar to show.