How to adjust the execution time of the task of Index Rotate

My graylog (5.2.2) configures the Rotation period to P1D (1 day, a day), but the Index Rotate job is executed at 8 o'clock, I think it is caused by the timezone (I am in the +8 time zone), how can I adjust it to 0 o'clock execution?

Adjust the timezone of the graylog or the time at which the indexRotating task is scheduled to be executed

## Why?
Avoid formerge action during non-idle periods

## Your Environment

* Graylog Version:5.2.2
* OpenSearch Version:none
* MongoDB Version:6.0.5
* Operating System:centos7
* Browser version: