I am trying to get the string between hyphen (-) which is before (+) upto next colon (:)
SELECT txt, 
       SUBSTRING(txt, CHARINDEX('-', txt), CHARINDEX(':', txt, CHARINDEX('-', txt)) - CHARINDEX('-', txt))
FROM test


or

SELECT txt, 
       SUBSTRING(txt, CHARINDEX('- +', txt), CHARINDEX(':', txt, CHARINDEX('- +', txt)) - CHARINDEX('- +', txt))
FROM test


fiddle