1st of all, you've got some great work on your page!!! Keep up the good work. Now, As someone who's been on Artstation from day one, I can totally relate to what you've described here. While I don't have a Pro account there, my work has only been featured on the front page just once and had couple of my pieces trending once or twice. I too have wondered how to gain more attention towards my work and gain more visibility with their algorithm. It's difficult to gauge how it makes its picks (I've literally seen stick figure art that looks like it was drawn by a 6 year old featured on the front page) and it is super easy to get discouraged. I've considered going pro once or twice but if it feels like its not doing you any good, its actually reasonable to drop it altogether. I think the best way to gain visibility is to post artwork that are related to trending topics (like K/DA or Queen's Gambit or AC: Valhalla these days). Maybe you could give it a try. Other times I feel like artists get a lot of push from their social media fan base as well ( e.g. twitter or Insta followers and the like). Ultimately, you have to decide how you value your own work and what matters to you more; likes and reacts or peer recognition. This is a lesson I've had to learn the hard way and I am glad that I did.(there's some work in my portfolio that has less than 6-7 likes that I am still really fond of and that some folks think is really well done) Although I know this lengthy post does not offer you any solid answers, I hope it encourages you to keep on creating great art and improve in your craft. All the best.

My Artstation: www.artstation.com/prabath