How do you learn new poker strategies, who do you follow, what websites, software, books, etc. do you recommend?
There are lots of options out there, but for me, the best coach out there is Jonathan Little. He has a number of books out there, varying from entry level rookie, right through to high stakes crushers.
He also has a website - pokercoaching.com - that has the most content of any online training site today. There are three tiers of membership; free, standard and premium. I would strongly recommend completing all the free content first to see how you get on and if you can afford it and your poker results justify it, sign up to the standard membership. There are often promotions available to great good discounts, so no need to pay full price. There is also a lot of his content on YouTube.
I recommend (actually Jonathan Little recommends) not watching Twitch streamers for anything other than entertainment. Often they are playing at a level much higher than you should be playing and therefore thought processes and plays that make sense for them will not translate to your games. Also, they will not have the time to talk you through their whole thought process, so it is difficult to really get a true understanding of why they do what they do.