Add ics feed as trusted instance

I would like to be able to add an icalendar to my list of trusted instances.

For mobilizon, there exists https://import.mobilizon.fr and they are right when they say: "Break down the walls of closed proprietary services to publish on the platforms of your choice"

I imagine this importer would crawl an ics feed and make all its entries visible in my gancio instance.

I was also thinking there could be a way of doing it with third party services, so like convert ical to ActivityPub-Instance and add this instance as trusted instance; or convert ical to rss and then to ActivityPub or a bot which publishes all entries of an ical calendar on mastodon or something like that, but I could not figure it out.