You have either made made some incorrect assumptions or have been given bad information/advice.
See the Journal Entries section of https://www.odoo.com/documentation/functional/accounting.html for information on how to setup these accounts correctly. You will be able to see the correct entries that are booked for each event.
Stock Input is a Balance Sheet Liability account to TEMPORARILY store the value of goods before a corresponding Invoice is generated to book the value of those assets is to Accounts Payable.
This account holds the corresponding CREDIT that matches the Inventory DEBIT booked to your Stock Valuation Account when items becomes yours, UNTIL the Invoice is received, entered and validated in Accounting.
Names for this account can be: Goods Received Not Yet Invoiced, Unvoiced Receipts, Purchases Clearing, or GR/IR (Goods Received/Invoice Received) Clearing - the Accountant, Bookkeeper, Controller or CFO is the person who can tell you which name they prefer.
It is incorrect to configure this as Inventory.
Stock Output is the opposite - a temporary place to store the value of the goods you deliver until you process an Invoice for them. Usually the balance in this account will only last for seconds or minutes, assuming you Invoice as soon as you Deliver the items.
It is incorrect to configure this as Cost of Goods.
Expense is the account used to book either expense (item purchased is not directly related to making a product ready to sell, such as Office Supplies, Janitorial Supplies, Shipping Supplies, etc) or Cost of Goods (item purchased is directly related to making a product read to sell, such as Packaging Supplies, Cables, Accessories, etc) when the Customer Invoice is validated.
It is incorrect to configure this as Goods In Transit.