Google Calendar API keeps returning empty result set with events.list

I have Google Calendar with multiple events, both single and recurring. Occasionally I run a script to refresh it by deleting all existing events and adding new ones, using the Google Calendar API.

To list the events I use, with no additional parameters: https://www.googleapis.com/calendar/v3/calendars/calendarId/events

The problem with this approach is that an empty result set is returned, along with a nextPageToken token. When I fetch the next set of results with the nextPageToken token, another empty set is returned. This loop continues forever.

If I use singleEvents=true then I do not get empty results, but this in turn creates more calendar entries to delete, since recurring events are expanded to single events.

Why do I keep getting an empty result set in the first instance?

What I tried:

Fetch URL: https://www.googleapis.com/calendar/v3/calendars/calendarId/events

Result: Empty result set, nextPageToken returned, infinite loop of empty results when fetching nextPageToken.

Fetch URL: https://www.googleapis.com/calendar/v3/calendars/calendarId/events?singleEvents=true

Result: Works, but more results than necessary for deletion are returned.

Example API response without singleEvents=true:

{
 "kind": "calendar#events",
 "etag": "\"p329vtmnsvedos0o\"",
 "summary": "Events",
 "description": "",
 "updated": "2025-07-01T12:26:06.035Z",
 "timeZone": "Europe/London",
 "accessRole": "owner",
 "defaultReminders": [],
 "nextPageToken": "CkwKPAo6CkwIvfvvwgYQmLiFigMSKhooChwKGmZxa2tzMmRjaGdodGtucmt1Mm5xc2pobDFjEggKBgiAhZm-BhoMCPenj8MGENCSitACwD4B",
 "items": []
}