From what i can tell, Reaper isnt a very straightforward Job in terms of approaching enemies. I think it is way better to resort to hit and run tactics to bait people (one at a time) into isolated corners and then overwhelm them.

A good way to do so, is to catfish them by staying at 50% HP and falling back to the next HP potion, only healing youself if it gets too dangerous, but not too much at once.

It will require some trial and error with the gap closer, but try to rely on it as much as you can, it is more worth than it seems.