My calendar app is asking permission to access my contacts.

Ah yes, modern software.

Every time I turn on the flashlight on my phone my Bluetooth headphones switch from my PC to my phone as an audio device... Really annoying

Makes sense right?

I’m so in the habit of denying anything asking permissions for anything out of the blue, a person from IT at my company had to reach out to check why my antivirus wasn’t configured properly. Apparently I’d dismissed the request out of habit. 😅

It's probably for birthday dates. So the calendar can show you when a birthday is coming.

I don't think you need to worry. Sometimes it may seem too complicated to give such permissions, especially in today's world where privacy and data security are important to us. For me personally, a useful resource for Iphone issues is https://setapp.com/how-to/..., which has a lot of useful articles. I personally had a problem with the display of contacts and was able to find a solution.