I can see the challenges with changing the decimal separator from comma to point in QuickBooks Desktop (QBDT),  @EthylicCedric. I'm here to help you resolve this matter.

We must enable this feature in the company preferences if you want to use the decimal point. By doing this, QuickBooks adds a decimal point to the item quantity automatically. You can take the next few steps to enable the decimal preference.

Here's how:

1. Launch QuickBooks Desktop.
2. Navigate to the Edit menu.
3. Click on the Preferences and click the General section.
4. Once you get into the My Preferences tab, you can place the checkmark for the Automatically Place Decimal Point tab.
5. After this, click the OK button.

Additionally, You might want to use some form templates so you can modify the details. QuickBooks contains the customization tools you need to make them so. Refer to this guide to complete the process: Customize Form Templates.

In case you need help with other customer tasks, click this link to go to our general topic with articles.

Let me know if you still have questions or concerns. I'm always here to help. Take care and have a wonderful day ahead.