There is a problem with the time display

There is a problem with the time display

Is it because I set it to the UTC+8 time zone? There's an eight-hour difference

Yes, Metabase translates database columns to a local timezone if set.

So do I need to delete both lines of configuration?

You can set the Reporting Timezone in Admin to the timezone you want Metabase to output dates and times as. Details on Metabase’s timezone support is here: