For those interested in challenging life and death problems, I am relaying here a three year old thread posted on stackexchange:
I would label this problem pro level, but I think there’s interesting reading materials for all levels in the answers. The takeaway is that you should not take for granted that a 3-3 invasion always works (which is unfortunately what one of the answer does).
I posted a first answer 3 years ago, and another one a couple days ago with some help from Leela Zero. If you have suggestions to add to the discussion, I’ll be happy to take a look.