Hello again everyone. I want to thank all the replies I received, it helped me to gain some perspective.
In the end, my pay turned out to be higher than I thought. Taiwanese handwriting is a disaster, I mistook a 3 for a 2, and it turns out my pay was a full 10k higher than I thought. Still not great, but it gives me the time to explore options for further teaching at a less hurried pace.
A new issue has started to rear its ugly head. First a bit of context: I’m a soft-spoken introvert, mild-mannered and polite when possible. And although I understand very limited Chinese, in practice I can’t understand what the kids are saying, like most foreign teachers. However, the daughter of the boss is half American, and I believe a lot of the assumptions in class are based off of her teaching experience. But she speaks fluent Chinese of course, so these assumptions don’t work for me or most FTs.
You know how children are. If there is the appearance of anything being unclear, they will take advantage. Especially the younger kids during short breaks, they mob me, and I need to fend off the touching hands. I have to, otherwise it’ll look on CCTV like I’m a foreigner who likes being touched below the belt by young kids. So I have to do something. At first I tried lifting them up, so their hands were reaching in the air instead of below my belt. Because they also wanted to be lifted up; I was becoming an amusement park ride! But the teachers warned me not to lift them up, it might hurt their arms. So, I resorted to redirecting their hands so they hug each other while I say “bao bao”. It has them in hysterics, because it becomes a ninja hugging game.
But all of this is basic self defense, because I can’t communicate in their language, and the ‘homeroom’ teacher just stands idly by doing nothing while I get attacked. It’s not that I particularly want to engage physically with these kids during breaks. And the Chinese teacher could easily establish order. And I also worry if one of these kids will get hurt.
One time, I was struggling to get them to pay attention because they kept coming up and trying to play with me. And then on the final minute of my lesson, the homeroom teacher says two sentences in Chinese, then all the kids go back to their seats, shut up and put their hands in the air. I was furious, but I stayed silent.
They can totally maintain order, help me out, but they just sit in the corner doing paperwork or checking their phone.
Anyway, the boss has now started entering my classrooms, interrupting my classes, and criticising me right there. Last Monday a parent complained that their older child could draw straight lines at the same age, but now the younger child draws ugly lines. And this would mean I’m a bad English teacher, ruining the school’s reputation, something like that. My colleague speaks a bit of Chinese and heard what my boss said in Chinese, and there was angry profanity.
It’s true that we haven’t focused much on how well the lines follow the dotted line, but it showcases how the FT will be blamed whether or not it was our fault, or even a real problem (young kids often develop at different cognitive speeds, but the differences all even out when they’re teenagers). And honestly, do you really need an FT to practice drawing lines straight? I understand my role is heavy on entertainment and even babysitting, but still, it feels absurd. 
Yesterday a child fell with a loud bang during a classroom game. She was ok, luckily, but shivers went down my spine. I need to know how liability is handled in classroom accidents, because these people absolutely will blame me personally if they can.
The boss and her daughter are becoming increasingly negative, and the job seems worse than anything I did in mainland China. There’s no quiet office, there’s no time to prepare sometimes, teachers don’t help maintaining order in classes with young children, notes on previous lessons are not well kept by the Chinese teachers, so even if I take material home, I just end up wasting my time, and I still have to improvise an 80min lesson.
Yesterday the class folder had no notes on the previous lesson (the boss’s daughter didn’t write anything down), so I ended up preparing a lesson based on the previous lesson note (wasted time again). Despite this, I could still improvise a decent lesson. She sat in my classroom and interrupted me 10 minutes before the end. She reminded me of a post-it that was in the folder (she didn’t write note of her lesson but she had made a post-it…?) which talked about a communication book. This book is half in Chinese, and it seems to be an evaluation book that gets filled in every now and then. It was never explained to me, but I still had to fill it in. 
“Right now in the classroom?” I asked. Yes, the kids needed to bring it home to their parents. So, I was sitting there doing 20 minutes of paperwork during a lesson (because paperwork is ok during a lesson in this school), and it ran late with kids getting impatient. It was utter nonsense, and appeared to be just to troll me and make me look bad in front of the children.
These people aren’t just trolling me, they’re actively showcasing my alleged incompetence. I have a lot of criticisms about the way the school operates and utilizes me, but I kept my mouth shut so far. 
Maybe it’s a way of protecting themselves, by shitting on the new FT, they can deflect blame for the school’s problems on to me. But it’s too much stress and I’m not getting payed enough for that BS.
Or it could be a prelude to guilt-tripping to accept worse employment terms because “I’m so bad.” 
Or I might be getting fired because they have another FT lined up? The last is very unlikely in Miaoli tbh, but can’t discount any possibility.
It all reminds me of my family motto: I always get the nutter. I’m mild-mannered, soft-spoken, introverted, not argumentative. Certain people (and I’m guessing cram school owners fit the profile) they take one look at my face and I can see them thinking: “I can mess with this guy. I want to mess with this guy. I’m totally gonna mess with this guy.” 
The funny part is, it’s very similar to how young kids behave naughty when they think they can get away with it. I expect better from adults, but some people take one look at my face and they can’t help themselves… 
Maybe I’m just venting. But any tips to prepare for a possible move to a different school will be taken on board. Thanks for reading!