Validation

Enable Unit of Measure:

Go to Settings Inventory

Tick the Unit of Measure feature. This will enable functionality to change the unit of measure from "Units" to other measurement units.

Enable Feature in Custom Module:

In the custom module, go to Settings Point of Sale Pricing and select POS Price Based Qty Button.

Configure Product Variant:

Open the product variant that you want to apply this functionality to in Point of Sale.
Navigate to Point of Sale Products Product Variant General Information
Tick the Price Based Qty option and save it.

Using the Feature in Point of Sale:

Open the Point of Sale module and select the product.
Below, you will see a button called Price Based Qty.

Enter the amount, and the system will automatically calculate the quantity for that amount. The calculated quantity will appear in the product line.

You can proceed directly to payment, and Odoo will function as it normally does for other products.
Note: If you haven’t configured the quantity based on price in the product variant, clicking the Price Based Qty button will display an error.