Calendar access on mobile

Are there any mechanisms, preferably free or included out of the box (but non-free can be acceptable), that allow a user to use a Calendar app on their phone (preferably the native app) to interact with their CRM Calendar?

The goal is to provide 1-tap direct access to the schedule for mobile staff so they can quickly see where they need to go next; and when they need to go there.

Currently we use CalDAV and a CalDAV connector to provide this functionality to mobile staff, but we’d like to be able to move the calendaring function in to SuiteCRM.

The latest SuiteCRM versions (7.11) have complete Google Calendar 2-way sync. So you can just sync the Calendars and use the default Calendar app on mobile.

There are also a bunch of SuiteCRM apps that add functionality to this and allow for more things. QuickCRM, SuiteMOB, and a bunch of others (easy to find on Google Play). You can check how much they let you do in the free version.

Using Google Calendar as an intermediary isn’t acceptable, due to data privacy concerns.

Ok, so check out the mobile apps. For example QuickCRM seems to include Calendar in the Basic (free) version.

I found that the built in iCalendar publishing URL does provide this functionality after setting a Publish Key, but the associated security mechanism is too weak, relying on “security through obscurity” with the Publish Key.

So far the only other solution I’ve found is https://www.sugaroutfitters.com/addons/activities-sync

Any other options? The CRM apps available are not sufficient - they require more than 1 tap to get to the calendaring data.

Thanks for reading and thanks in advance for any input and suggestions.