NextCloud makes sharing calendars pretty easy. You can get an embed link with text to stick in to your website, and a public page for people to view the calendar online. If people want to get a version of the calendar that will be kept up-to-date that they can use in their own calendar setup (on their phones, or in Thunderbird or wherever) that's a bit obtuse, but still doable. If you right click and 'Copy Link Location' the 'Download' button you've get an address you can use.