Welcome to the Community, Skeksis.
It's good to hear you were able to find a related article about posting deferred GST in QuickBooks Online. At the moment, we're unable to turn on the label for 7A for deferred GST in the GST report. The feature you're looking for is unavailable in the current GST set up in QuickBooks Online. Deferred GST is currently very rare, just like a WET tax, due to the low demand, this is why it is not supported. I can lodge feedback to our customer feedback system to let our Product Development team know. And hopefully, this gets added in the future release.
As a workaround, you can record a deferred GST liability using the steps attached to this link Record a deferred GST liability. Or it's also recommended you lodge BAS directly to the ATO portal.
Stay in touch if you have other questions regarding QuickBooks Online. I'll make sure to get back to you right away. Have a nice day!