Display powersave only blanks, but does not turn off - RPi4

I used Ubuntu 22.04 (with wayland) on Raspberry Pi 4, and it seems like the power-saving feature in gnome does not properly turn off the screen.
My attached display does not go into a low power standby mode. Although the screen after X minutes is dark but still has backlight.

OS: Ubuntu 22.04 jammy
Kernel: aarch64 Linux 5.15.0-1014-raspi
DE: GNOME 41.7
X: Wayland

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: gnome-power-manager 3.32.0-2build2
ProcVersionSignature: Ubuntu 5.15.0-1014.16-raspi 5.15.46
Uname: Linux 5.15.0-1014-raspi aarch64
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: arm64
CasperMD5CheckResult: unknown
Date: Fri Sep 9 22:09:30 2022
ImageMediaBuild: 20220809
SourcePackage: gnome-power-manager
UpgradeStatus: No upgrade log present (probably fresh install)