You can't really target interactive readers specifically. You need to separate the two: Attract as many readers as possible, interact with those readers in ways that builds an engaging community.
@ninjashira said it, but I will second because this is a very accurate way to represent things. Statistically a very small percentage views become subs, of those subs, a small percentage will like, and of those who give likes, a small percentage are even willing to comment.
I totally get the "I'd rather have interactive readers!" mindset, but I'd caution everyone to appreciate all your readers. The vast majority of people just aren't interactive, but if they're subbing to you, they're someone who loves and supports your stories. That still has value, even if it's not as fun as a comment!
So how do you create engagement?
Creator comments! You set the stage and tone for interaction following your episode. I have kind of a range of go-tos for this, from talking about my process making the episode, whats happening in it, or something in my life from that day or that week. Follow that up with a relevant question to your audience every few episodes.
Otherwise, reminding people that liking and comments helps both your motivation and the comics visibility occasionally. I usually do this at the end of a chapter, or on an event update (like the tipping events).
But if the "quiet" is bothering you, I suggest looking at your number of subs, no matter how big or small, and think of them as individual people sitting on their phones or at a computer smiling to themselves as they read something you made. Those are still real people. And I don't know about you, but even 5 strangers liking my story enough to read it kinda blows my mind? This is just how I think and what works for me. Not knocking anyone for desiring likes and comments (they are fun and exciting!)