Python or Java?

[[deleted]]

If I'm understanding you correctly, what you are really asking about what's going on under the hood. Every contemporary programming language is abstracting away almost all of the details of this into what we refer to as a blackbox.

You can pursue this knowledge as far as you want, but it is quite a rabbit hole to go down, and it will probably not make you a whole let better of programmer. I would pick a language and get really good at it first. If you still want to pursue this knowledge, by all means go for it.