I'm in the same boat, the X-T2 has been my main camera for a couple of years, and I constantly have GAS and think of 'upgrading' to one of the cameras that you mentioned. But, like you said, the T2 is a great camera. I love the images that this camera produces, and neither the X-H1 nor the T4 are going to be noticeably better, if better at all, as far as image quality.
Admittedly, IBIS would be nice, but I've never had a camera with IBIS, so I don't miss it, and the lenses you have, 16+23, aren't really lenses that scream out for IBIS. Whether or not you need it, or that it will help capture better images is a decision only you can make.
For what I shoot, the AF on the T2 gets the job done. Would I like to have better AF? sure why not? but the AF on the X-H1 will be basically the same, or at best, only marginally better. By all accounts the AF of the T4 is better, I haven't tried it so I can't speak from personal experience, but $1,500 is a lot of money to me for better AF that I rarely feel I need (plus the flippy screen makes the T4 a no go for me)
Supposedly, Fuji will be making some big announcements in May, which is really right around the corner, so unless you REALLY need IBIS, or the AF on the T2 is hindering your ability to capture great images, it might be best to sit tight and see what's coming next. If nothing else, new announcements usually lead to lower prices for older models on the used market.
Good Luck with your choices