So,. I could talk for hours on setup and gear, I work as a sound engineer.
I would say.. and not everyone might agree with this.. but if you want to learn to mix.. its far more important to learn how things sound on your setup. An approach to perfect neutral audio is a long and complicated journey. You're headphone are a good set of headphones.. I would go for studio monitors next. And mostly.. listen, listen, listen. Get to know your favorite songs really well and use them as reference.
There's not really rights or wrongs, experience is important in this.. to know your ears and the system and goal your working with. Offcourse neutral is good.. but you can train your ears to make decisions when mixing without a perfectly neutral setup.
Learn how the digital instruments you use, would sound accoustically as a real instruments and where they fit wel inside the mix. Technique and tricks can be learned, but experience and workflow in how you approach the topic is what I've always found more important
All ears are different and mixengineers always make different decision on their opinion or the artists they are working with. So there's no right or wrong. Criticism is constructive and an opinion of where I, or someone else would make a different decision. (I also am never happy with my entries and keep hearing things I'd like to change!)
If you need help or struggle with a certain feel free to ask for help or insight from different composers or engineers!
Sorry for the long reply, but I hope that that helps, feel free to hit me up if you struggle with some technical aspects 😉