I understand your frustration at working in a bad situation. I would however point out an interesting turn of phrase you use.
"I seem to be a magnet for scummy, dishonest people who are just a nightmare to work for."
It is not possible to be a magnet for people you work for, only a magnet for people who work for you. So that begs the question, why do you keep working for scummy, dishonest people?
As someone who has suffered more poor situations, bad employees and miserable owners than I care to remember, over the years I have learned to observe what makes a kitchen more likely to be a place I want to work and which circumstances will make me miserable so on those rare occasions when I have to look for work I can increase the likelihood that I will enjoy my job.
Unfortunately a restaurant can enjoy a great reputation with the dining public and be a bad place to work and learn anything. So going to work for what is reputed to be the "best place in town" doesn't necessarily guarantee anything.
In no particular order, before applying for a job anywhere,
1. I eat there if possible.
2. If I can't afford to eat there, I walk in when it does not appear to be extremely busy and ask to see the menu. While doing so, I spend three to five minutes "reading the menu" but also observe the staff, the environment, the condition of the dining room, the kind of customers. This is necessarily a brief experience but does provide some information.
a. Do the employees generally seem helpful, friendly and courteous? Do they appear to be in a genuine good mood or masking a bad one? Do they appear to be engaged in doing their jobs or standing to the side muttering to each other? Is it possible in those brief moments to observe any interactions between the FOH and BOH? Did it appear to be a calm, professional interaction?
b. Is the dining room in good repair? Is the carpeting run down and in need of replacement? Does the room look fresh and inviting or dated and rundown?
c. Do the customers seem to be enjoying themselves or do they appear anxious or distracted, not engaged in convivial conversation? Anyone smiling at each other or the staff? Does anyone arrive or leave while I am "looking at the menu"? How does the staff handle the greeting and seating of the new arrivals? How does the staff handle the customers when leaving?
3. Does the menu look interesting? Is there anything I would like to cook? Is it too large, too small, too silly, too hip, not hip enough? Does it mention anything about "made in-house", farm raised, sustainable, seasonal, or anything else that reflects current trends?
4. If I decide to apply, I make sure to see the kitchen before I accept the job. Either I walk through on my way to see the chef or I specifically ask during the interview. Sometimes when I am finished with reading the menu, I will ask to use the bathroom. Sometimes you can pass by the kitchen door and may get a glimpse of the kitchen.
5. Is the kitchen clean? Are the burner knobs on the stove missing? Is the floor of the line littered with debris? Does everyone seem to be focused on their work? Does the mood seem to be miserable or quietly professional? Are work stations neat and organized or cluttered and messy? Does anyone say hello, nod or otherwise acknowledge me? Is there any interaction between FOH and BOH while I pass through and was it a professional interaction or tense and angry? Is a loud radio playing so the staff has to raise their voice? What if any communication do I witness between members of the kitchen staff? Is it positive or tense?
With practice, this can all be done quickly and you can at least get the general mood of a place. And after so many years in the business, you should be able to pick up pertinent observations without much effort.
6. I use the grapevine and rumor mill to my advantage. Does anyone else want to work there? Do others in the industry discuss the place as a great place to work or a place they would like to work? A place to avoid? No reputation? Is the owner known for their gambling/addiction problems? Is the owner's reputation one of tough but fair or a total idiot? Do I personally know any employees? Are they professional or professional idiots?
So generally speaking, I now know pretty much whether or not the place is worth applying at. If I have done my homework and no red flags come up, I'll apply and hope for the best.
Having done all of the above and then getting the job, I arrive feeling much more confident that my chances for enjoying my work rely much more on my ability to get along with my co workers and work hard consistently.