That's awesome your beta likes your work, and you have people interested in your manuscript. Honestly, and I always tell writers this on my blog, if you want to get somewhere with your writing, you need to go where your audience is.
I don't do comics, but if you're gaining more of a following on Webtoons, I get why you want to focus your time there.
I'm almost 90% sure I'd get a better readership on Wattpad for my stories (especially since I started off there), but I don't like the company's business practices. Do what is best for you and your career!
I'm sure in time Tapas will have a bigger user base, but I can understand not wanting to wait around for that - time is precious, and we have to make the most of it.