I have written a query which does what I require bt I was wondering if there is a more efficient way to run this as it is taking hours to bring back a few hundred rows and it should run to about 160k records I have added subquery to create the previous year count which is causing the performance issues

SELECT 
main.date,
main.course_group,
main.StudyModename,
main.campusname,  
main.course_name,
main.CAS_Required,
main.StartMonth,
main.StartYear,
main.DepositPaid,
main.current_year_count,
(SELECT COUNT(DISTINCT sub.appidjoin)
 FROM [report].[YoyNumbers] sub
 LEFT JOIN [dbo].[pbi_applicationattributes] sub_b ON sub.appidjoin = sub_b.appidjoin
 WHERE sub.ProductStartDate >= '2024-08-01'
   AND sub.date <= main.date
   AND sub_b.course_group = main.course_group
   AND sub_b.StudyModename = main.StudyModename
   AND sub_b.campusname = main.campusname
   AND sub_b.course_name = main.course_name
   AND sub_b.CAS_Required = main.CAS_Required
   AND YEAR(sub.ProductStartDate) = main.StartYear
   AND CASE 
       WHEN MONTH(sub.ProductStartDate) IN (1,2,3) THEN 'Winter' 
       WHEN MONTH(sub.ProductStartDate) IN (4,5,6,7) THEN 'Summer' 
       WHEN MONTH(sub.ProductStartDate) IN (8,9,10,11,12) THEN 'Autumn' 
       ELSE NULL 
   END = main.StartMonth
   AND
           CASE WHEN sub_b.CAS_Required = 'no' THEN 'No'
         WHEN sub_b.VisaPaymentMadeDate IS NOT NULL THEN 'Yes' 
         ELSE 'No' 
    END = main.DepositPaid