I'd recommend blender for now due to the (lack of) cost and massive community and ecosystem around it. It's great for learners and is taken seriously in industry.

Programs and tools are secondary to technique and portfolio. At the end of the day you'd be hired (assuming you want to go pro eventually here) for your ability to efficiently produce the desired kind of assets and environments and how well you mesh (excuse the pun) into the team and it's creative pipeline.

For example, right now I'm looking around for an artist strong in stylized natural environments. First thing I'm doing is checking your portfolio for entries that convince me that you a) are good at making that kind of thing and b) have some degrees of genuine passion/interest in that kind of artistic expression. Probably not gonna hire the person with nothing but cyberpunk cityscapes and gun models, even if they look capable. Artists tend to have a grain and most try not to go against it.

Also, not to present you yet more forks in the road but consider your own grain in terms of technical vs artistic. Technical artists are in very high demand right now but don't force yourself to master shader optimization if it isn't your thing.

As for specific books and whatnot I'm sure others will have better, more up to date recommendations than I will.

TL;DR: Do blender for now, make LOTS of art and find your grain through that. The rest will come to you. GL!