Backing Up Windows Terminal Settings with PowerShell - Source: https://jdhitsolutions.com/blog/powershell/7422/backing-up-windows-terminal-settings-with-powershell/

Backup-WTSettings.ps1

[CmdletBinding(SupportsShouldProcess)]
Param(
    #how many backup copies should be saved
    [int]$Limit = 7,
    #backup folder
    [parameter(HelpMessage = "Specify the backup location")]
    [ValidateScript({Test-Path $_})]
    [string]$Destination = "C:\users\jeff\OneDrive\windowsTerminal"
)

#Actual path to settings.json file - you will want to uncomment this line
#$json = $ENV:Userprofile\AppData\Local\Packages\Microsoft.WindowsTerminal_8wekyb3d8bbwe\LocalState\settings.json

#comment out or update to reflect the location of the settings.json file to backup.
$json = "C:\users\jeff\OneDrive\windowsterminal\settings.json"

Write-Verbose "Backing up $json to $Destination"
Write-Verbose "Get existing backups and save as an array sorted by name"

[array]$bak = Get-ChildItem -path $Destination -Name settings.bak*.json | Sort-Object -Property name

if ($bak.count -eq 0) {
    Write-Verbose "Creating first backup copy."
    [int]$new = 1
}
else {
    #get the numeric value
    [int]$counter = ([regex]"\d+").match($bak[-1]).value
    Write-Verbose "Last backup is #$counter"

    [int]$new = $counter + 1
    Write-Verbose "Creating backup copy $new"
}

$backup = Join-Path -path $Destination -ChildPath "settings.bak$new.json"
Write-Verbose "Creating backup $backup"
Copy-Item -Path $json -Destination $backup

#update the list of backups sorted by age and delete extras
Write-Verbose "Removing any extra backup files over the limit of $Limit"

Get-ChildItem -path $Destination\settings.bak*.json | 
Sort-Object -Property LastWriteTime -Descending |
Select-Object -Skip $Limit | Remove-Item

#renumber backup files
Write-Verbose "Renumbering backup files"
<#
You can't rename a file if it will conflict with an existing file so files will be copied
to a temp folder with a new name, the old file deleted and then the copy restored
#>
Get-ChildItem -path $Destination\settings.bak*.json | 
Sort-Object -Property LastWriteTime |
ForEach-Object -Begin {$n = 0} -process {
    #rename each file with a new number
    $n++
    $temp = Join-Path -path $env:TEMP -ChildPath "settings.bak$n.json"

    Write-Verbose "Copying temp file to $temp"
    $_ | Copy-Item -Destination $temp

    Write-Verbose "Removing $($_.name)"
    $_ | Remove-Item

} -end {
    Write-Verbose "Restoring temp files to $Destination"
    Get-ChildItem -Path "$env:TEMP\settings.bak*.json" | Move-Item -Destination $Destination
}

#show current backup files
Get-ChildItem -path $Destination\settings.bak*.json | Sort-Object -Property LastWriteTime -Descending