I need to share a public calendar with a possibility to sync new events in their smartphones

I need to share a public calendar with a possibility to sync new events in their smartphones

Hi, I'm organising events for my social media followers every now and then and I would like to share a link to my calendar that they can import to their smartphone calendar app without the need to have a Zoho account or installing some additional apps.
I shared iCal link recently, it worked, but no syncing. I read the calendar FAQ and it only offers some options with additional apps to be installed or a need to have a Zoho or Google account.
Can you recommend any easy option for my followers to get info about my events directly in their phones?

Thanks