Look the thing you need to understand is that in the West their is an expression 'silent approval', we'll say little when we approve of something but we'll complain hard when we don't like something. I get it, it sucks, you got significantly more complains previously than cheers, its the same for every single other people in the entertainment industry or hobby... whatever stretch of it you go thru people will raise a storm against anything they dislike and will largely say nothing if they approve, unless they have some particular agenda regarding the subject.
Its why Western civilization is pretty much crumbling nowadays because people in power have been listening to those few loudmouthed assholes and just decided it would be what would gain them the most approval, doing the worst things possible. Reality wise however its not the case, the majority approve of other things than the ones you hear about, its just those few vocal mongrels are damn loud and get heard the most.
Now the reason you get vocal support for what you wanted the story and characters to be and how things previously were is because you basically made the story far less palpable for many people. So while you have appeased a vocal minority you did so at the expanse of a previously silent majority, now we are being vocal in defense of the story and characters as it / they were, and against what it turned out to be. Its a shame for you and for us that it has come to this point, that all the people that actually loved this story and characters are effectively losing them over a small group of assholes which are just here to impose their way on everyone else.
But it doesn't have to be this way, we can go back, you could easily just bring back the previous version and pick it back up, some Devs did so when they did like you, doing some mistakes in how they developed their game, they figured they had went the wrong way and just erased the new update and brought back the old one and continued back from where it was. Heck if you like some of the new characters you can bring them all back into the old story, you can continue your original story while melding the new characters into it fairly simply.
Or you might decide you prefer the new set up over the previous one, I saw some good to it, and some bad... nothing tend to be perfect. You could adjust the shot, removing or changing back some stuff and keeping others, I mean for example I personally favor old Yoon appearance wise, if you were to alter things to bring her back to what she looked like it might help significantly getting the pill passed for most of us. If you have as little investment as most of us do in the new male MC you could strip him back out while keeping the rest of the new story, the point is tell the story you want to tell, have the characters you want to have, and don't pay attention to the complainers trying to make it something you don't want. Its never too late to make things right as you want them to be right, it will only be too late if you give up and surrender to the assholes.
Look right now you are not in a good place, I get it, I do spend alot of time in a bad place myself, maybe it would be better if you focused on your two other games for a while, take a few months to figure out how you really want to proceed with this game, by taking a break from it for a while, Kathoey has been on the back burner for quite a while, so it could be worthwhile to pay some attention to it and let things calm down here for your and everyone's sake. Afterward whatever you decide to do with this, so long as its the story as you truly want it to be told and characters as you truly want them to be, it should be fine and most of us should be able to get over this hurdle and all be in a better place.