Personally, I think that the focus on on the phrasing itself, which as you mentioned are all more or less synonymous anyway, is letting the underlying challenge get away from you. You can safely use any of them, but that there's other stuff that can be done that's more important.

Any time you can convincingly explain exactly why you're suggesting something it makes the suggestion itself seem much more reasonable, and it's a valuable check on your own reasoning. From there, you can reword the explanation itself in creative and valuable ways to give feedback. If you get really good at this, then a lot of times you don't even need to ask for a specific change, you can just turn the problem you're seeing (I.e. 'explanation' from above) into a question. I'll give an example.

Let's say you want to say "Extract this to a separate function". Ok, now, ask yourself why? So you tell yourself, "Because we may want to use part of this function again, but not the rest of it, and the exact same behavior can be achieved with little to no additional effort by function composition (or whatever you do in your PL)" Ok, that seems reasonable, but maybe now it may be perceived as a little too abstract to someone else, especially if they're just trying to get their work done. But you can take solve that by taking the above 'explanation' and make it concrete. One good way to do this is to think of a counter example, where it clearly doesn't work how we want.

As an example, let's just pretend that they're doing something like parsing a thing from a database into some strongly typed thing, and then doing foo work on the strongly typed thing. You can ask yourself then, well if we were unit testing this, we won't care about the parsing part, we can just start with the strongly typed thing as the precondition of our test, and then isolate what we're testing to just be the foo functionality. Now you have a simple example that you can rephrase into your original feedback.

This thought exercise all leads to the feedback going from "extract this to a separate function" to "Does this mean that unit testing the foo feature requires a parsing step for each test case?"

Maybe that's a silly, contrived example, but I've found that if you even capable of going through this thought process then not only do people receive your feedback much better, but also you just tend to think of much better feedback altogether. After a lot of practice you end up being able to think this way very quickly and then you can focus on adjusting the wording based on your relationship with that person.

At the end of the day, it's not what we say that really matters, it's how someone feels they're being regarded by one their peers. If they sense contempt, then it won't matter how politely or expertly you word things. Having extremely well thought out why's in your back pocket, and being able to provide concrete counter examples just makes it clear you're not wielding your review power just to talk but to illuminate the problem to them. It also solves the problem of when you're the idiot (as happens to all of us from time to time), by forcing you to actually justify your feedback before you share it.

When I've done this, I've noticed that my reviews become faster, and I focus on stuff that people don't think about. It makes the code better and then people will actually seek out your review.