"Modern" News link appearing across all our team sites

You can use the below PowerShell PnP script to remove "News" navigation from all Site Collections and sub-sites.

$o365=Get-Credential
Connect-PnPOnline -Url https://<tenantname>-admin.sharepoint.com -Credentials $o365
function fixupNavigation ($web,$url) 
{
  Remove-PnPNavigationNode -Title News -Location QuickLaunch -Force
  Write-Host $Url ": News Removed"
  $subwebs=$web.Webs
  $context.Load($subwebs)
  $context.ExecuteQuery()
  foreach ($subweb in $subwebs)
  {
   Connect-PnPOnline -Url $subweb.Url -Credentials $o365
   $context=get-pnpcontext
   $subconweb=$context.Web
   fixupNavigation $subconweb $subweb.Url
  }
}
$Allsites=Get-PnPTenantSite
foreach ($Allsite in $Allsites)
{

  Connect-pnpOnline -Url $Allsite.Url -Credentials $o365
  $context=get-pnpcontext
  $web=$context.Web
  fixupNavigation $web $Allsite.Url

}