When a opportunity is created, the close date is set to the related Payment Txn - Bank Deposit Date and NOT the transaction date.

The primary reason for this is some organisations will integration Opportunities to their Finance system and this reflects the date the funds were actually received in their bank account.

If you need to amend this, please work with your Salesforce admin, Salesforce consulting company or our Premium support to create a flow to adjust this.  Alternatively, simply add a field on the Opportunity with a type of Date and an API name of Transaction Date.  The like for like copy of fields from the Payment Txn will then populate this field.