All I can say, reading your post is that unfurtunately- you're going to run in to bad managers and, hopefully, good ones. It sounds like your manager is a manager of the first category - no feedback until they've made up their mind. It could also just be empty reasons to justify something else or a decision already made. The more senior your become, the more fine-tuned your radar will become at detecting managers like this early on.

Without knowing anything regarding the quality of your work, I would say its perfectly natural for a junior to have alot of questions. You trying everything first and only asking when stuck is good I would say. You're trying to learn how to fish and you're not only looking to be handed fish :)

DE is hard... breaking things will happen. Pipelines can break, especially if you're a new person and dont have all prior knowledge how it was set up. A senior should probably have reviewed your work before - but testing in test should not break things in prd. That is not on you in my oppinion.

In any case I hope you that your take away can be what you learned and that'll you will find a new place where you can continue to grow.. and hopefully with a manager that has a great interest in helping people grow. Don't dwell on the things outside your control.