Collapse Rows into JSON Value

I have the following code to Collapse rows into JSON and XML PATH WITH STUFF Operation is very slow.
Looked into alternatives and couldn't find anything suits my needs.
Is there better way to collapse rows and create JSON String ?
Thanks,
I90Runner

SELECT 
				@AffiliateID AS AffiliateID,
				AttributeName, 
				AttributeValue
			FROM 
			(	SELECT DISTINCT
					Attribute AS AttributeName,
					(	SELECT 
						'['+ STUFF
						(	(	(	SELECT ',' + Value AS [text()]
									FROM @TMP_ATTRIBUTES
									WHERE Category = t.Category
										AND Category IN 
										(	SELECT Category 
											FROM dbo.Attribute WITH (NOLOCK) 
											WHERE AttributeType= 'CP.AffiliateAttributeList'
										)
									ORDER BY Value
									FOR XML PATH(N''), TYPE
								).value('.[1]', 'varchar(max)')
							),
							1, 1, ''
						)+ ']' 
					) AS AttributeValue
				FROM @TMP_ATTRIBUTES t
				WHERE Category IN 
				(	SELECT Category 
					FROM dbo.Attribute WITH (NOLOCK) 
					WHERE AttributeType= 'CP.AffiliateAttributeList'
				)

I90Runner