Go to Settings > Focus, select "Add filter" and pick your desired calendar for that focus!
Now you have filtered out all unnecessary events.
How to Show only the most relevant calendars with Focus Filters
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How to Share your full calendar in a few taps
Go to a calendar (or create a new one) and tap the "i" to its right.
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7 iPhone Calendar App Features for Better Event Management
How to use Siri with Calendar, drag-and-drop events, Focus filters, and share calendars on iPhone