Selfish or self aggrandising thinking, feelings of superiority, lack of attention to others

Are you describing something which can happen without proper technique/guidance or something which inevitably happens? And I guess I'm wondering the same for the rest of your list of changes.

It happens for almost all practitioners, one problem is that the secular practise doesn’t offer the “save all suffering beings in the cosmos” narrative that Buddhism does, and so it cannot offer a way forward beyond the insight and into compassion. It usually doesn’t even try to.

I found it interesting because while I can see how the other things in your list would naturally happen as attachments lose power, I don't see why an increase in neurosis would be a necessary or even a common result. (For context, I've been meditating daily for a year and a half, for 30-60 minutes and this simply hasn't happened to me yet. In fact, if anything, the opposite happened, where I engage less in self-aggrandizing behaviour.)

Have you not heard of the spiritual ego? Most practitioners eventually grow a big ego around their practise. Chogyam Trungpas book “Cutting through spiritual materialism” is all about this

Now that you've mentioned it, I remember hearing about the term but I always took it as a possibility, especially when misapplying practice, and not a necessary part of the path. My own path so far seems to be confirming this notion of mine so the things you were saying piqued my curiosity to learn more.

Will I become more self-absorbed and grow feelings of superiority as I continue to meditate? I don't know. But I will still try and see for myself.

It's an obstacle on the path to surpass, it's just that most people do go through it to some degree. For some it's severe: my old teacher told me about a co-student who solved Mu and then became extremely arrogant and left the sangha saying he doesn't need them anymore. For some it's much more mild