Caldav sync for outlook users, serverside

There is a util for client-side sync of Outlook caldav to nextcloud, details are described here;

This will work great as long as you have Outlook installed. But this does not work for all of our users, for example, i don’t have Windows or Outlook on my system. Also, im assuming you must have outlook running.

I would like an app that can do server side app for caldav data. I would like to remove the dependency on Outlook and query the server directly, in our case these are Exchange servers, so query ews:

As i’m asking here, it could be a nextcloud market app. Would it be hard to create something like this? I think i’m willing to offer a bounty or such for the development as i think this clould be much wanted as most of our clients use Exchange.

I also asked the makers, to do it (but not as a nextcloud app);

You can use any other calendar software supporting CalDAV. On apple devices, the calendars support it, for Thunderbird you have the lightning extension. But I’m not sure, are you asking for a desktop client? Or mobile?