Passing parameter in query dynamically

-- I have a query that is stored in a table column, the query contains a parameter 

-- I tried to pass the parameter, but failed. How can I accomplish this task?

CREATE TABLE #testFullQuery(longString varchar(Max))
INSERT INTO #testFullQuery(longString) VALUES ('SELECT * FROM @NewValue');

DECLARE @SourceCode nvarchar(MAX);
SELECT @SourceCode = longString FROM #testFullQuery
DECLARE @NewValue VARCHAR(MAX) = 'TableName';  

DECLARE @FullQuery nvarchar(MAX);
SET @FullQuery = '';
SET @FullQuery = @SourceCode 
EXEC sp_executesql @FullQuery;
print @fullQuery, @NewValue

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