You really know your stuff bro. Physics is such an interesting subject, wished I had majored in it.First of all, it should be clarified that the confusion regarding the big bang that two particles collided with each other and the universe was formed comes from a United States program in which the guest was one of those who saw the traces left by the big bang Microwaved, the guy was on Nationwide and with a short period of time he couldn't have made any sense of how it really happened. The point is that all the existing matter in the universe was concentrated in a diameter not greater than the diameter of our solar system and this is where thermodynamics comes in, all this ball of mass would have to have been very small with the same density and temperature at each point of it to give rise to what Alan Guth described as the inflationary period in which the temperature of this mass had to rise to such a magnitude and thus expand.
Regarding the formation of stars, it is necessary to take into account how the atoms fuse and how each one of them is composed, but at least with the stars, it is only necessary to focus on the Helium, which is their fuel, as the stars are spending this fuel lose electrons by nature, the stars are losing mass but in turn the Helium begins to fuse with other Helium atoms like this, forming heavier atoms such as carbon, neon, oxygen, etc. and this is where I realize that I was wrong that I didn't mean star formation but how stars die lol.
I would have to look up the papers I read it in, it was a long time ago but it was a reliable source from what I remember. (I could say that a friend did the experiment and that it worked for him but it was just an exchange of words at the time and I didn't get to see the jars)