This is mainly about terrain exploits which have to be viewed but the Korrak revenge twinking can be summarized as
- Get legacy gear with gem slots and set bonuses.
- Wod pre-legendary ring + exalted ashen verdict ring from ICC.
- Legendary cape if you have it.
- If you use azerite traits stack them ilvl doesn't matter
- Use oils (eg wizard oil) and level 60 appropriate consumables (they are cheaper and just as effective as hi-level).
You can do a mountain of dps with the above.