Is it okay to ask for hints during a system design interview?

I sometimes get stuck on a very specific technical aspect during a system design interview, like how to achieve exactly-once delivery with a particular messaging system, or a very nuanced consistency model. When that happens, is it generally okay to ask for a hint from the interviewer? My concern is that asking for a hint might be seen as a lack of knowledge or problem-solving ability. But proposing a solution that I'm only half-confident in feels risky too, especially if it leads down a wrong path. What's the best way to navigate this? Should I try to articulate my thought process and the options I'm considering, even if I don't have a definitive answer, and then ask for their perspective if I'm truly stumped?