Thank you for saying this. Honestly, probably could have cut a total of four years of waste out of my life by just knowing the company was not a good fit for me.

I used to stay at a place and say "Ok, maybe its me, what can I do to put the most effort in, and maybe that will change how upper level toxic management trickles down and fundamentally changes how politics over rule technology and data based decisions, or hard workers over letting the old boys club stay comfortable"

I actually used to believe something I could do would change that or, if I worked hard enough or tip toed around management to make them feel comfortable about their culture and still find time to do the work I felt was important in my own time without offending people who felt comfortable consistently underperforming and had positions of superiority over me, that I would be recognized for my work, work ethic etc.

no, that's not the case. Leave and leave fast because while I was the one who eventually chose to leave those companies, those companies are never going to acknowledge how much you are worth, or that they don't deserve you. They care about self preservation and staying there no matter how well you perform is not going to help you get a better job elsewhere.

if it's short enough of a time then you don't even have to put it on your resume you worked there.
A lesson I wish I knew fresh out of college.

of course, all of these things about me are true. There is something you can always do to improve yourself, or change your mindset to help yourself change how you approach frustrating situations to change how a team might respond to a solution or a challenge, and foster a more positive environment.

The biggest red flag?
When you are constantly challenging yourself to grow and change to meet the needs of the company and find novel ways to contribute in your spare time, and basically having the "how can I rise to the challenge. How can I challenge myself? How can I grow?" mindset when management does not have a "how can we stay open minded and rise to meet the challenge" mindset. It's not just not a good fit for you, but it will be damaging to your career to be at odds with superiors who will feel threatened by this mentality and approach you have. It will be obvious to your peers this is the case, and it will make them look bad. When your authority is based on optics and politics, people like you are a threat to the company.

the other and only red flag you need is when the company doesnt see people as its most valuable asset, it sees large amounts of funding, and pretty buildings and initial investment as it's most valuable asset. Stay away.

and as a last note on this big red flag, again, all the things the companies I worked for did, was cool, fit my skills and interests, experience in school and previous jobs. If I tell you "hey I worked here developing cutting edge technology and heres some metrics of our stats in the market" people would say wow thats cool.

And it was cool, and it could have been cool, but people ruined it. It's really about the people, no matter what you are working on. If you don't have high quality people, then you can't have high quality products or services. Period.