i had the same thing where best i could get when i relaxed was a narrow merge, and when i crossed my focus was too close to my face to be helpful, plus strain.
sudden clicked after fully crossing 5 or 6 times and then relaxing and was able to hold the "3rd image" very easily. felt like magic, even hardest difficulty was obvious
For me it just does not work right now. Maybe I have bad eyesight, I wear glasses and am past 40. I believe I was able to do this trick in past though. At the very least on psychedelics (various kinds). This also made me able to relax my eyes more, wheras I normally have too much pressure on them according to optician.
sudden clicked after fully crossing 5 or 6 times and then relaxing and was able to hold the "3rd image" very easily. felt like magic, even hardest difficulty was obvious