Interestingly, that thought triggered a response to me: "How do I know my higher self is aligned with my highest good?"
You will just know. This will happen through additional work while on the path. That doesn't have to be in this life, and that's not at all a negative thing. You may come out of this life and have the memory and/or realisation hit you, and join with that aspect — this may happen consciously, while out of body at some point in this life.
For me, a door suddenly opened; it wasn't about belief. It wasn't faith. It was an understanding and acceptance. It was after a lot of work too, and I was spending a lot of my spare time working on my self for years. I had an income to allow me to do that too, at the time. One of my stronger psychic abilities is finding the most efficient methods for spiritual development, which helped me a lot in a short period.
One thing that's important to remember is that you are your higher self already, so this is how you are right now, and that is fine. You will just have more access to it, at another point, and based on many factors your understandings will change, whatever direction that may be.
Sometimes we are told things, even by that famous HS, which we need to know in the moment, even if that contradicts something we trusted. It's all for a good reason, as what we are told, and if we take that seriously, is going to direct our path to a degree; not everything we are told is the 100% truth, but our actions and decisions leading us forward is exactly what we needed for our learning and growth. This may cause a sense of betrayal, and further confusion, but that's just how things work. In the end, we get there.
What if all the madness here has actually being organized by asshole higher selves dooming the lower ones to suffer for their egoistical aim of having experiences?
You're spot on, this is exactly how it works, but there are levels from there, to here, of beings who manage many aspects pertaining to the madness, in terms of what is allowed and what is not allowed. But there is no ego involved from up there, ego is a construct made for human growth and learning and is not carried over to higher levels of existence. Duality is important for growth here, and the levels of duality, the balance, relates to the astrological cycles, the periods of thousands of years that come and go. Other beings help maintain that.
Bad is not bad, it is perceived as bad without fully understanding why it is required for growth.