Bentham might apply if you consider the overall outcome: is the work your company does positive or ethical for the majority of people the majority of the time? It seems like the “greatest good for the greatest number” would allow for some small unethical aspects so long as the outcome is good for the majority. This could also be seen as a shortcoming in that philosophy because it justifies some pretty terrible actions for the greater good (some of which, like the Manhattan project and its outcome, are mentioned elsewhere in this thread).
Kant might make you look at your company and imagine that all companies acted that way as a way to reason ethically. If all companies acted the way your company acts would that be good or bad for humanity? Kind of like the golden rule, but more rational.
There are many more to consider but it’s my view that most of them will get you to the point where you probably shouldn’t work for an unethical company, even if your particular work or area of focus is perfectly ethical. Mainly because you working for the company allows or helps it to exist in some way, and we don’t want unethical companies to exist. So maybe you could reason your way into working there if your sole focus was finding a way to destroy the company somehow. Otherwise it’s probably better to work elsewhere.