Hi KBinCT,
For help with the Date & Time on your iPhone when using Calendar, check settings for the "override the automatic time zone" feature. You can navigate to Settings > Calendar to view details. The guide here also has the steps. Customize your calendar on iPhone
If this is an iCloud calendar, you can also check the settings from the iCloud website. Add calendar events in other time zones on iCloud.com
"Note: Changes you make to the time zone appear on every device with Calendars turned on in iCloud settings and time zone support turned on. Time zone support must be turned on individually for each device.
- In Calendar on iCloud.com, click
in the bottom-left corner, then choose Preferences. - In the Advanced pane, select “Enable time zone support,” then click Save."
If the issue continues, reach out to Apple Support directly to further assist.
Contact - Official Apple Support
Contact Apple for support and service - Apple Support
Best.