I think it definitely depends on your relationship with the recipient. While I do think most of those are better options, I wouldn’t say they’re necessarily what you should write.
Agreed, it is not always prudent to be overly assertive.
For example, I may be working with someone else on a project that is not time sensitive, but for my own planning I like to stay up to date on progress. I absolutely would reach out to someone with a "Just checking in, how are things going with X" because, well, that's honestly all I'm doing. Checking in.
Meanwhile, saying "When can I expect an update?" is almost like saying "I don't think you're going fast enough and I'm getting impatient," which sends the wrong type of message, makes me seem like a hardass, and might impact the quality of work if the other person suddenly feels rushed.