I'm in trouble because I can't refuse a job

If everyone is forced to overwork because it's a black company, they probably think “it's okay for me to refuse and cause trouble to someone.”
I don't know how much of an outlook can be made for work, but it's like drawing up an itinerary, grasping the fact that it's useless, and showing it.
It's a different story if someone is being manipulated only by you in order to have fun. You have to tell them that you feel it's unfair. That state of affairs is already causing trouble to others from an overall perspective, isn't it?
Or, if your abilities are low and you can only produce results lower than those around you, then give up on “having an impact on your personal life” for a while.
In any case, I can't say too much if I only write from your perspective. Too few things can be conveyed by the expression “the air of the place.”

Not being able to do it doesn't work.
You get paid, so do whatever you need to do at any cost.
Work overtime and work on holidays. It's a matter of course.

Clench your teeth
Come on, be an adult.

If other employees feel the same way, employees should act in unity with each other.
Otherwise, you might end up being the bad guy all by yourself.
Black businesses are illegal.
Trying to make illegal profits by doing illegal business is negligence on the part of management.
However, when all the other employees are convinced, that is, when everyone is aware of the black state and is motivated to succeed at work, the story is complicated.
In the case of a group of people who work with enthusiasm like student club activities, there will be a temperature difference between you and your colleagues, even if you only calmly bring up legal arguments alone.
Nonetheless, it is foolish to destroy your body due to overwork.
I work for a living, but when my life is destroyed because of work, it's just plain bad.
The fact that health is more important than work should be the same for everyone, so if you use health first as a weapon, you may be able to refuse.