Disclousure. I'm sitting here in NZ with my 5 weeks paid leave plus 25 sick days, wfh flexibility and a boss that refuses to answer questions outside of normal office hours reading your horror stories of incompetent bosses and pathetic excuses for employers.
That said if your treated this badly this often it means that you accept it. Business are allowed to treat their employees this way because there is nothing better for them.
Why don't you do make a competing business. I know it's hard but if these incompetent morons can do it you can do it better, pay more, do better by your employees. Hell scrap employees altogether make everyone a share holder, if you can't afford it by yourselves look for a collective funding, hell your healthcare system basically runs of GofundMe. Put it up there.
Like I said just a thought from the bottom of the world.
GL and unionize.