Robert, have you worked night shift before? Individuals have a wide range of reaction to it - for some it’s little different, for others it just plain kicks their butt.
Talk about “mixing things up” and “keeping the body guessing,” though… I think it need not be a bad thing, i.e. losing gains you’ve already made. If anything I’d say it could be a good thing, though perhaps at the cost of a little more tiredness than usual/taking a while to adapt.
If you can really control your situation, then keeping your current routine wouldn’t be a bad way to go, in my opinion. Where I’ve seen people struggle is when they can’t or won’t really go fully “on night shift.” They are tired in the morning, after work, and they go to bed right away. Then they wake up at noon or early in the afternoon, have a long time before they go to work, and end up really tired at the end all over again. Or situations like talking to their spouse/kids at certain times of the day mean they are awake when they should be sleeping.
I’ve done a ton of nightshifts, both before going keto and after. I kept it as much the same as I could, i.e. if on dayshift I went to bed at 11 p.m. then on night shift I’d aim for 11 a.m. For eating ketogenically, it does switch around for me, since it’s often eating the breakfast a hotel offers; on dayshift I eat before going to work; if on night shift I eat after working. If you can control when you eat, so much the better.