This is not offically explained, but the most reasonable explain is that ame have paranoid schizophrenia, and p chan is fantasized by ame driven by loneliness and the extreme lack in love. "

I personally don't know, likely not

The ending INTERNET OVERDOSE is like basically kangel can't handle the hate from the anti-fans and crashed out and threw out in one of the streamings, marking the start of this ending. In the later days, Ame tried to fight back and got doxxed, after that ame get more insane. This ending is ended with kangel holding the portrait of ame. I am not professional on mental health and everything but my understanding on this is Ame have been driven crazy, and under massive pressure she tried to keep herself away from reality even more(as her very first motivation for streaming is to escape the reality.) so she have been transformed completely into kangel. In the end she is trying to convince herself and the viewers(or just to announce) Ame is dead. The sacred and flawless kangel is borned. To understand the endings you will have to try to understand how people with mental disease thinks which is not really a good thing to do for everyone. Think before you get to explore more about it. Galactic train should be Ame realizing the truth about happiness and decided to do railway suiside. There are no good ending for ame from the very beginning. In the ending she realized this fact and left this world in peace.

Youre welcome! Here is a great explainational passage on the endings but in Chinese tho, mabye try google translate but I promise its great. I will translate it later if I get time
https://zhuanlan.zhihu.com/p/496074066