Most of my chapters wrap up with unanswered questions. To me that's good. It's intentional. It lets the reader be curious about things and want to find out more. Sometimes these questions are answered in the first paragraph of the next chapter, other times the answer is several chapters away. I've had more than one person read chapters of my WIP and complain about not having something explained to them. Am I wrong? Or is it good they have these questions?
As long as there's a nice balance of content and mystery, it'll be fine; I won't care about the answers if I haven't initially been given enough to chew on. Betas are good and bad, so I won't say you need changes, but I generally want my story to leave readers making theories and thinking about possible outcomes rather than solely complaining there's no answers yet. Like every other bit of feedback, just stew on it some more and maybe feel out alternatives. Perhaps the story would benefit from a little more foreshadowing or clues. Maybe the readers are just impatient.
It's very good that they have these questions so long as the most important ones are answered. "Will Senator Davies reunite with his family?" for example.
Cliffhangers are good for the most part. At times they can get a little cheesy. But if you're writing's not cheesy to begin with (which its not) then there's usually not much of a chance for that. I think you've got to make a judgment call on the people who're telling you its a problem. Are they experienced readers/writers/editors that are saying that its not working for X, Y, and Z. Or are they just average reader types that are pissy about being left in the dark while you make them wait for the next chapter? If they can give you a decent reason why they think its not working then maybe take it into consideration. If they're just saying, "I don't like it! [pout]" then maybe take it with a grain of salt.
I think there's a difference between having a chapter end with a can't-wait-to-see-what-happens-next vs a withholding of facts or evidence in the hope it makes a reader ponder possible outcomes. Example of the first type: I have my protagonist open a door partway only to have it kicked in violently which throws her backward. She stumbles over some furniture and knocks herself out ("the world went dark") as she hears her roommate scream. I don't really have an example of the second type (maybe someone could offer one) but it goes back to my annoyance reading many of the classic 'whodunit' books where the writer intentionally withholds the crucial piece of evidence until the 'reveal' scene at the end. Oh sure, you might be able to guess it...given a million years and enough monkeys on typewriters, but it is an intentional pirouette away from allowing the reader to possibly figure things out for themselves.
I think the other type would be something like the protagonist opens the door has a shocked face or screams in terror or something and then thats the end of the chapter. Kind of like the literary equivalent of click bait. "You wouldn't believe what happened when this protagonist answered the door." - Yeah that can be a real turn off. Probably something writers will have to become more and more wary of as people get sick of seeing that kind of nonsense on their social media feeds all the time.
I think as long as its balanced its fine - a certain amount of mystery is nice I went through a faze of intentionally trying to make EVERY SINGLE CHAPTER end with a cliffhanger, it was exhausting for me as a writer, and not pleasant as a reader. As a reader it started pissing me off a lot because it seemed forced - so I reckon, as long as its balanced and "casual" it would be fine
