Hi Cowboy469,
Thank you for giving us the chance to assist you with your iPhone 8Plus. You can count on us to do our best to assist you or get you pointed in the right direction.
We understand that you are experiencing crashes when using the Calendar app and the Clock app. We recommend updating your iPhone to the latest version of iOS 14 if you haven’t. While it isn't inherently assured that an update will resolve the issue, updating to the latest version of iOS for your device can help isolate potential software issues. Kindly secure a backup and update.
How to back up your iPhone, iPad, and iPod touch
Update your iPhone, iPad, or iPod touch
Is the device set to the correct Time Zone? Also, is the Date & Time set automatically? You can confirm these details under Settings > General > Date & Time.
Are experiencing the issue when using a Wi-Fi network, cellular data, or both?
Also, let us know if you are using a VPN on your device, on your router, or access point.
Do you have a different Apple device that is signed in to the same Apple ID? If yes, are you experiencing a similar issue with your other device?
These details can help us in isolating the issue.
Please keep us posted.
Cheers!