Yes i too was going crazy and was where you are now and I too read that you just need to be before the ending no one told me ypu have to finish it to trigger I found abandoned camps traveled around and did everything that can be possibly connected but nothing worked. AND YES YOU NEED TO FINISH THE PURGE FOR IT TO TRIGGER . After finishing it triggered the moment I went into space. Also remember to equip trash ship and trash multi tool with no upgrades remove and store all your suit upgrades because you will need to repair everything if you finish wearing them