This could be the result of another plugin or your theme messing with the WordPress system date/time.
You can pinpoint the problem using the Health Check & Troubleshooting plugin. This plugin allows you to view you site as an administrator with all other plugins disabled and using the default theme, while keeping you site fully intact for other visitors. Then you can see if the problem goes away, and enable other plugins one by one to isolate the conflict.
I tried with the disabling other plugins but not success yet meantime i go through the wp system time and settings and attach photos of configurations.
I tried with “Twenty Twenty-Four” calendar not appear with that. I send you screenshots of the calender its mapped with wrong days. In initial loading its load with 2023 november like C1 image and its wrong. I i click on next arrow head it will show 2024 December like shown in C2 image and also in the address bar it shows like “?grid-list-toggle=grid&month=jan&yr=2024” for the December 2024.
Im using a customized theme created by me called “ Andrew-powell Theme CMM”and its working fine with other plugins also. I attached screenshot of view with the Twenty Twenty theme.