#3 To test the waters with Edge
Again, we'd like to emphasize on why WWE needs to be very careful with Edge - not just physically. WWE usually has a good reputation of taking care of their performers who are out injured and we're sure Edge will be handled well in that regard.
The other aspect is the creative one - a department which WWE has struggled with in the last few years. While we do admit that RAW has been far better creatively under Paul Heyman, there will always be skepticism with how WWE could handle Edge in this day and age.
When you consider how different things are when he last wrestled in 2011 and now, the said skepticism is more than justified. Whichever stage it is, WWE may want to test the waters with Edge before looking at other potential opponents.
Luckily for him, he has a lot of great potential opponents should he be able to remain fit in this interesting 2020 run.