To split the range to multiple rows, each represents an hour (or a part of an hour), you can join your table with a numbers table. If you don't already have a numbers table, you can use a common table expression instead. There are plenty of ways to do that, specifically since we're talking about only 24 rows, I would simply use a Table Value Constructor :

SELECT H
FROM (VALUES(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12),
  (13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24))V(H)

Join that to your EmployeePunch table will give you the number or rows you want:

WITH cte AS 
(
  SELECT H
  FROM (VALUES(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12),
  (13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24))V(H)
)
SELECT EmployeeId
  , TimeStartRaw
  , TimeEndRaw
  , H
FROM EmployeePunch
INNER JOIN cte
    ON DATEPART(HOUR, ActualStartTime) <= H
    AND DATEPART(HOUR, ActualEndTime) >= H

This will give you the following table:

Now there are a couple more tricks to do to get the time of day and calculate the number of minutes per row: Using cross apply with TimeFromParts to convert H to time of day, and using dateDiff , Lead and IsNull to get the minutes per row:

WITH cte AS 
(
  SELECT H
  FROM (VALUES(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12),
  (13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24))V(H)
)
SELECT EmployeeId
  , TimeStartRaw
  , TimeEndRaw
  , HourOfDay
  , DATEDIFF(MINUTE, HourOfDay, ISNULL(LEAD(HourOfDay) OVER(PARTITION BY EmployeeId, CAST(TimeStartRaw As Date) ORDER BY H), TimeEndRaw)) As MinutesWorked
FROM EmployeePunch
INNER JOIN cte
    ON DATEPART(HOUR, ActualStartTime) <= H
    AND DATEPART(HOUR, ActualEndTime) >= H
CROSS APPLY (SELECT TIMEFROMPARTS(H,0,0,0,0) As HourOfDay) As T

Note the PARTITION BY part of the LEAD - I'm assuming your table contains more than one shift for more than one employee.

You can see a live demo on db<>fiddle