I want to delete my whole stock list and load a complete new one i see i cant delete the items, i must make them inactive, is this correct?

Yes, making the items inactive is the correct way to remove them from your active inventory list in QuickBooks Online.
 

Regarding the Cost of Sales adjustment, this can happen when inventory items still have quantities on hand when they are made inactive. QuickBooks will automatically adjust the remaining inventory quantity to zero, which can affect your Cost of Sales account.
 

To avoid this adjustment, make sure the inventory quantity is zero before making the items inactive.
 

To adjust the quantity:
 

1. Go to +Create, then under Other, select Inventory Qty Adjustment.
2. Enter the necessary details, such as the Adjustment reason and Inventory adjustment account.
3. Under Item details, select the PRODUCT/VARIANT you want to make inactive, then set the NEW QTY to zero.
4. Select Save or Save and close.
5. Once done, you can make the items inactive.

If you have already made the items inactive and QuickBooks created an inventory adjustment, review that adjustment before making any changes. Deleting or editing inventory adjustments can affect your financial reports, so we recommend confirming the correct treatment with your accountant.

If you have additional questions, feel free to reply to this thread.