Xiaomi 12’s screen automatically turn on

[rainw]

Hello, my Xiaomi 12’s screen automatically turn on around 9 p.m. (UTC+1) every night. It just lights up without any notifications.
It turns on the screen very punctually, sometimes it's 21:00, sometimes it's 21:01 or 21:02. I've been observing it for several months...
I don't know what happened. Has anyone encountered this problem?

my phone:
Xiaomi 12
rom: xiaomi.eu_multi_XM12_V14.0.7.0.TLCCNXM_v14-13