o365cli-wp-props.ps1

$site = "https://contoso.sharepoint.com/sites/site1"
$pageName = "AModernPage.aspx"
$webPartId = "af660fc1-c09b-4c15-b093-2b74b047286b"

$choice1 = "Choice 1"
$choice2 = "Choice 2"

# Put all the WebPart properties in a PowerShell hashtable
$webPartProps = @{
    myChoices              = @($choice1, $choice2);
    description            = 'My "Awesome" WebPart';
};

# Build JSON string from PowerShell hashtable object
$webPartPropsJson = $webPartProps | ConvertTo-Json -Compress
# Make sure to add the backticks, double the JSON double-quotes and escape double quotes in properties'values
$webPartPropsJson = '`"{0}"`' -f $webPartPropsJson.Replace('\','\\').Replace('"', '""')     

o365 spo page clientsidewebpart add -u $site -n $pageName --webPartId $webPartId --webPartProperties $webPartPropsJson