Struggling with building my first test class so I can deploy an Apex trigger. The trigger converts an Opportunity/Opportunity Products into a Sales Order/Order Items.

Receiving the below error message:

System.DmlException: Insert failed. First exception on row 0; first error: FIELD_INTEGRITY_EXCEPTION, field integrity exception: PricebookEntryId, unknown (versions 3.0 and higher must specify pricebook entry id, others must specify product id): [PricebookEntryId, unknown]

Below is my test class:

public class Create_Order_Test_Class {
    @isTest static void testSetup(){
        Account testAcct = new Account (Name = 'My Test Account');
        insert testAcct;

        Opportunity oppt = new Opportunity();
        oppt.Name ='New Test Deal';
        oppt.AccountID = testAcct.Id;
        oppt.StageName = 'Closed Won';
        oppt.Amount = 24000;
        oppt.CloseDate = System.today();
        insert oppt;
        
        Order ord = new Order();
        ord.OpportunityId = oppt.Id;
        ord.AccountId = oppt.AccountId;
        ord.EffectiveDate = oppt.CloseDate;
        ord.Status= 'Draft';
        ord.Pricebook2Id = oppt.Pricebook2Id;
        insert ord;
        
        Product2 p = new Product2();
        p.ProductCode = 'attribution_annual';
        p.Name = 'Attribution - Annual';
        insert p;
        
        String pbs = Test.getStandardPricebookId();
        
        List<PricebookEntry> pbes = new List<PricebookEntry>();
        pbes.add(new PricebookEntry(Pricebook2Id = pbs, Product2Id = p.Id, UnitPrice = 24000, IsActive = true, UseStandardPrice = false));
        insert pbes;
        
        Test.startTest();
        Map<String, String> productsMap = new Map<String, String>();
        for (PricebookEntry x : [Select Id, Product2.Name from PricebookEntry where Product2.ProductCode in ('Standard Price Book')]){
            productsMap.put(x.Product2.Name, x.Id);
        }
        update testAcct;
        update oppt;
        OpportunityLineItem oli = new OpportunityLineItem (OpportunityId = oppt.Id, Quantity = 1, UnitPrice = 24000, PricebookEntryId = productsMap.get('Standard Price Book'));
        insert oli;
        Map<string, string> items = new Map<string, string>();
        for(OpportunityLineItem x: [select id,PricebookEntryId from OpportunityLineItem where OpportunityId =: oppt.Id]){
            items.put(x.PricebookEntryId, x.id);
            
        OrderItem oi = new OrderItem(OrderId = items.get(oli.OpportunityId), Quantity = oli.Quantity, PricebookEntryId = oli.PricebookEntryId, UnitPrice = oli.UnitPrice);
        update oi;
        Test.stopTest();
        }
        
        }
    }