May is similar to asking permission. Can is similar to "am I able" Like "Can I drive the car" (am I able to drive the car) "May I drive the car" (do I have permission to drive the car)
So for your example, I would say yes it is correct.
Is this the correct way to use the word may? "May this distance only be temporary"
It's correct, but I'd be inclined to change the order slightly. I'd prefer "May this distance be only temporary," but that's just me.
Blue Lou is also correct. If you were using it as a question it would be better to ask, "Might this distance be only temporary?" But I don't think you intended it that way.
I think you're sentence should start with will . I think may is asking permission for something. Like :,May I eat the freaking chocolate bar I bought for my self before you eat it because it's MINE ! Will you please not be a jerk and eat my freakin chocolate bar because it's MINE? 😡 I may be wrong though . Lol :) that last sentence I used confused me with the May thing and was not intentional at all :) may is also the month before June. That's all I got