I think I have made a temporary solution by modifying the date as follows (see image) but I think it is not the best solution.
Any suggestion?

Hello,
Thank you for contacting Rank Math today.
I have raised this problem with our dev team and we will be getting back to you in a short while.
Looking forward to helping you. Thank you.
Hello,
Can you please give us some more details of the issue? Where did you change the timezone code? In Rank Math plugin or in the TranslatePress or in the theme file?
You shouldn’t change any code in the plugin files. The Sitemap is showing the correct date, I am not sure if it’s because of the code you added.
Looking forward to helping you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.