Probably will run a little faster with dynamic SQL though.

DECLARE @SQL NVARCHAR(MAX) = ''

DECLARE @MyString VARCHAR(100) = 'aaabbcdefgh'

;WITH Replacements (n,a,b) AS (

SELECT 1, 'aaa|bb|c|d|e|f|g|h','11|2|3|4444|5|6|7|8'),

Transform (ItemNumber, a, b) AS (

SELECT ItemNumber, MAX(a), MAX(b)

FROM (

SELECT n, ItemNumber, a=a.Item, b=NULL

FROM Replacements

CROSS APPLY DelimitedSplit8K(a, '|') a

UNION ALL

SELECT n, ItemNumber, NULL, Item

FROM Replacements

CROSS APPLY DelimitedSplit8K(b, '|')) a

GROUP BY n, ItemNumber)

SELECT @SQL='SELECT r=' + s + '''' + @MyString + ''',' + (

SELECT '''' + a + ''',''' + b + '''),'

FROM Transform

ORDER BY ItemNumber

FOR XML PATH('')) + 's=''' + @MyString + ''''

FROM (

SELECT 'REPLACE('

FROM Transform

FOR XML PATH('')) a(s)

--PRINT @SQL

EXEC (@SQL)