Enable "Light Mode" at 6:30am daily using this Windows Task Scheduler XML file

Light_Mode_Enable.xml

<?xml version="1.0" encoding="UTF-16"?>
<Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
  <RegistrationInfo>
    <Date>2022-10-23T19:30:00.0000000</Date>
    <Author>SCI\SpiralChaotic</Author>
    <URI>\SCI\LightModeEnable</URI>
  </RegistrationInfo>
  <Triggers>
    <CalendarTrigger>
      <StartBoundary>2022-10-23T06:30:00</StartBoundary>
      <Enabled>true</Enabled>
      <ScheduleByDay>
        <DaysInterval>1</DaysInterval>
      </ScheduleByDay>
    </CalendarTrigger>
  </Triggers>
  <Principals>
    <Principal id="Author">
      <UserId>%ComputerName%\%Username%</UserId>
      <LogonType>S4U</LogonType>
      <RunLevel>LeastPrivilege</RunLevel>
    </Principal>
  </Principals>
  <Settings>
    <MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
    <DisallowStartIfOnBatteries>false</DisallowStartIfOnBatteries>
    <StopIfGoingOnBatteries>true</StopIfGoingOnBatteries>
    <AllowHardTerminate>true</AllowHardTerminate>
    <StartWhenAvailable>true</StartWhenAvailable>
    <RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable>
    <IdleSettings>
      <StopOnIdleEnd>true</StopOnIdleEnd>
      <RestartOnIdle>false</RestartOnIdle>
    </IdleSettings>
    <AllowStartOnDemand>true</AllowStartOnDemand>
    <Enabled>true</Enabled>
    <Hidden>false</Hidden>
    <RunOnlyIfIdle>false</RunOnlyIfIdle>
    <WakeToRun>false</WakeToRun>
    <ExecutionTimeLimit>PT1H</ExecutionTimeLimit>
    <Priority>7</Priority>
    <RestartOnFailure>
      <Interval>PT1M</Interval>
      <Count>3</Count>
    </RestartOnFailure>
  </Settings>
  <Actions Context="Author">
    <Exec>
      <Command>%SystemRoot%\system32\WindowsPowerShell\v1.0\powershell.exe</Command>
      <Arguments>-NoProfile -NonInteractive -ExecutionPolicy Unrestricted $RegPath = 'HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize'; New-ItemProperty -Path $RegPath -Name SystemUsesLightTheme -Value 1 -Type Dword -Force; New-ItemProperty -Path $RegPath -Name AppsUseLightTheme -Value 1 -Type Dword -Force</Arguments>
    </Exec>
  </Actions>
</Task>

Almost 100% based on this Windows Central article.

I changed powershell.exe's command switches to include -NoProfile, -NonInteractive, and -ExecutionPolicy Unrestricted.
For semantic purposes, I slightly changed the PowerShell code so that it reads as follows:

$RegPath = 'HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize'
New-ItemProperty -Path $RegPath -Name SystemUsesLightTheme -Value 1 -Type Dword -Force
New-ItemProperty -Path $RegPath -Name AppsUseLightTheme -Value 1 -Type Dword -Force

I also made some adjustments to the task's "Conditions" and "Settings" tabs.

Usage:
See the comments for this gist's partner, Dark_Mode_Enable.xml, which I recommend using in conjunction with this one.