The "delivery due" date column has been removed from the core quoteline report as it is not supported in a lot of ERP systems. If you customise it back in for a supported ERP system, the toggle in the Settings panel doesn't work, as the 'QuoteLineDeliveryDue' field is not set to 'Editable'.
The field is still editable on a per-line basis by editing the individual line and updating the value in the slide-out panel. However, it is unclear in the CRM why the toggle doesn't affect the field if you customise it into the quoteline panel and we could look into making this more obvious.
