If you are unable to see the Connect to ATO option in your GST center to enable direct BAS lodgement in QuickBooks Online, it could be you have enabled the option already.
I recommend contacting out Customer Care Team. That way, one of our care agents can check the QBO file and verify if you have enabled the BAS e-lodgement or not.
Furthermore, know that to complete the BAS e-lodgment set up you need to nominate Exactor as your software provide with ABN 61 612 826 605 in your ATO Access Manager account or when calling the ATO.