You may have ruined the plant by growing at 24/0, but it is most likely a case of bad genetics, sadly something that seems quite common with autoflowers and the reason I will never grow them again. The breeder suggested 18/6 as optimum for a reason, plants need a dark period during every 24 hour period to finalise their photosynthesis and have a correct metabolism. By not giving your plants this dark period for so long, perhaps the plants metabolism is completely out of order and this may be a contributing factor in the plant being unable to flower normally, (but most likely bad genetics).
I would suggest growing much superior photoperiod plants in the future, they are far more genetically stable, yield more and are far easier to control when it comes to size and flowering.
I do not believe autoflowers offer anything that can not already be achieved with well sorted and genetically stabilized photoperiod plants.
Of the autos I did grow in the past, those bred by Sweet Seeds seemed to be the most reliable, especially their genetics.
At this stage it is hard to say what you should do, persist and see what happens, but unfortunately, starting again may be the most realistic option, as plants that I have grown that look like yours, end up yielding very poorly with buds made up of sparse calyxes with small leaves elongated on long thin stems and with very few trichomes. Obviously a difficult decision after so much time and effort and I sympathise with you.
Hope this helps in some small way.
Regards, Organoman.