If you haven't come across their stuff already, Socialism For All (also on SoundCloud, Spotify, and via podcast amongst other options) covers a huge amount of articles, speeches, and ebooks. They offer a really broad range of stuff which is mostly theory-oriented.

I'd also urge caution about getting into factionalism. It's okay to have positions and to have values but there are things to be learned everywhere and if you get too invested in dogmatism and investing a lot of yourself and your politics into a particular faction, especially when you are still new to all this, then that can become a major obstruction to the learning process. It is far better to say that you don't know something or that you don't know enough to make a call on a particular movement or event in history than it is to jump to a conclusion without investigating the matter thoroughly.

One example here is Che Guevara. He is called The Butcher of La Cabaña by Cubans who fled after Castro came to power because he oversaw hundreds of executions at La Cabaña.

That seems pretty cut and dried, right?

The problem is that the executions were done after a judicial process that the Cuban government held that was modeled after The Hague as a war crimes tribunal. The people who were sentenced were found guilty of egregious crimes against the Cuban people and it was only those who had substantial evidence against them who were sentenced to execution.

Imagine a civil war, one between the radical left and a far right government. How many people could you imagine committing war crimes in that situation? Hundreds? Thousands? Even more?

Of course 500 executions is a high number and you are welcome to disagree with capital punishment or to question whether each person was actually guilty of the charges they faced. The judicial process is not 100% and it never will be. But that being said, you'd be able to find 500 people in the US government alone who are indisputably guilty of war crimes, with a small mountain of evidence to back this up. And that's without even mentioning the people who are serving in the US armed forces.

What I'm driving at here is to be deeply skeptical and not in the sense that you deny evidence and regress into trusting your gut instinct or the prevailing narrative but rather to be very skeptical about convenient narratives and the situations where people give information that is quite shocking on the face of it in order to nudge you towards a particular conclusion. Ask yourself what you know about the subject and the surrounding context before you make a judgement call. Be okay with not knowing and in acknowledging when you don't know enough; ignorance which is accounted for is the first step on the road to knowledge. Embrace this fact and avoid the streamerbro urge to concoct hot takes based on zero foreknowledge of a subject.

It's all about learning, growing, and fighting for a better world. Don't fall into the trap of treating it like it's teamsports.