This is a really old topic so you might have found the answer.
Though from what I believe I will share my experience.
“ What are some ways to get people interested and invested in a story” That’s the whole question that needs to be answered.
Actually the answer lies in the question actually. “Get people interested in your story” get it? You need to invest your time and effort into reading, subscribing, liking, and leaving a comment on the works you like. Now as busy as a job that may sound, you can do it from 10 mins to 1 hr a day thats all. Just be consistent, review a few works, invest your metaphorical “0.02 cents” into someone else and eventually you will get that investment back double. But never EVER Tell people “Oh by the way i have a comic, please check my comic” etc. Be genuine and energetic in your comments, engage with other people around webtoons, and eventually you will get people saying “do you have a comic. you do? Lemmie check it. Oh wow this is good. And you already have 5 chapters? Awesome. I read all of them and can’t wait for the next one.”
I hope this helps and if you know something as well I’d love to learn from you. I am always open to new ideas and if they work better than mine i would always try them out.
Good luck!