I've been in a position where I had to find my next opportunity. While I was considering options, I asked a ton of questions and got to know the people/tech/processes extensively, and I believe I got a better offer because of it.

That’s great to hear. Any tips on how you modulated your questions? I think it’s possible the spirit of the inquiry was the same, some do it better.

One strategy is to ask questions in a more positive/balanced way. e.g.: "Do you unit test?" is a yes/no question, and if the answer is no, it doesn't leave much room to give a positive answer to the question. Compare this with "What is your testing strategy; what do you think you do well, and where could you improve?" gives you at least a set of tradeoffs.

Basically, you want the interviewer to highlight potential problem areas, without speaking about their organization in a way where they can't say anything positive about what they do. You can find these details out without giving a laundry list of explicit red flag type questions.