This could be unrelated to your performance though, maybe they went with another candidate, maybe they pivoted and don't need the position they were hiring for, or maybe the CTO wants to hire their nephew. The takeaway in my opinion is to reflect and think of any shortcomings. If you can't think of any, accept and move on.
It's totally OK to judge, one of the reasons I made this post was to get some raw feedback. If the most common reaction is that I come across as arrogant and the unreasonable party here, I'll do some soul searching around that :)
And you bring up a good point, but I don't like to think in those ways because it takes agency away from myself. Can't fix a problem I had no control over.
And couldn't agree more with the focusing on myself and to do further upskilling. I'll continue working hard and hoping that in another 6 month's I stand a better change of getting more interviews.
Thanks again for taking the time to answer!