Slight update to this: I gave one more attempt at the "normal way" of aligning yourself (pick shot image when up, fall straight into line, stay completely still), figured out a few tricks and things to help me do it more consistently and now switched to using that for 99.9% of shots, instead of aiming while down. The only exception are jump shots, but maybe I'll switch that over too some day if I figure out a more consistent way.
This doesn't really invalidate any of my points, since I didn't claim that the aim-when-down method would be better if you are able to do the normal way well enough, which now clicked for me, and didn't before.
And I wouldn't say it was a complete waste for me, since I'm still a relatively new player (3 years), the journey of using both methods and and being able to play at a relatively good level (600-650 fargo) while aiming down definitely taught me a lot about how different parts of the body affect your consistency, and gave me a lot of knowledge about how and why various things work or don't. And I wasn't hitting a plateau either, I've been slowly but steadily improving, I just immediately found the whole "normal" process much faster, easier AND more accurate for most shots, when a few things finally clicked, and I figured out how to drop down into the shot consistently enough to not cause misses due to that if done properly.
So, all in all, just like I said originally, good gimmick if all else fails for you, but now I can say with even more confidence that you can and should do it the normal way, and I'm glad to have figured it out now instead of later, since this has improved my game a lot in just a few days. My previous record of consequent 9-ball break-and-runs in practice (no BIH or anything, if no ball drops in break the streak ends, so real deal) was 4 racks (once), and now I did a 6-pack which just felt overall more effortless than before. My shot selection and CB control is obviously the same, but being able to pot those semi tough cuts much more consistently was enough to get an immediate noticable result.
So, if someone has the same issue of not being able to get good results the normal way, get a coach. If it doesn't click for you and you know it's not just that you haven't put in the time with their suggestions, get another coach. I happened to figure this out on my own but you don't have to wait for that moment and surely a good coach or a few will be able to guide you to that same progression much faster and with less risk of incorporating suboptimal habits.