2-way sync between calendars from different providers

This is a very practical feature, especially for Apple fans.

We're often forced to use Apple Calendar for private use and Google or Microsoft Calendar for business use. But we'd like these calendars to be synchronised in both directions for many reasons. Morgen could help doing this because it's a service that integrates all these calendars.

I'm currently using https://onecal.io/ for that, but guess what, you have to pay for it. I wish I didn't have to pay for anything other than Morgen, given the price!