iPhone 7: 5.44x2.64x0.28 4.87oz
iPhone xs: 5.65x2.79x.030 6.24oz
I wonder if anyone feels the same as me and finds the size may be a deal breaker.
The jury is still out. It's only been a day. However, at this point, I'm leaning towards returning it and keeping my 7. On paper, the difference in size between the 7 and xs didn't seem like much. But in reality, it is significant - for me. The xr is even bigger than the xs.
I moved from an iPhone 6 (same size as your 7) to the iPhone x in December. Before I bought the X, I compared the size and feel of the iPhone X to the iPhone 8 and 8 Plus in the store. The X felt like a good compromise size in terms of display to size ratio, but the iPhone 8 size felt just right... probably because I was so used to my 6.
I often use two hands to use my iPhone (hold in one hand and operate with the other, or hold and operate with both hands for landscape orientation), but it's still important to me to be able to use my iPhone with one hand because sometimes that's just necessary. I did not feel like I could operate the iPhone 8 Plus with one hand. It was awkward and it felt like I would easily drop it. The iPhone X (same size as XS) was a bit of a stretch for me, but not nearly as awkward or precarious feeling. Of course much depends on your hand size and preferred grips. I am a 5' 9" male with what I suppose are average size hands.
I have been using iPhones since the 3G, and I can remember when the iPhone 6 felt huge. It was a bigger leap in size to go from the iPhone 4 or 5 to the iPhone 6 than it is to go from an iPhone 6/7/8 to the iPhone X (at least in terms of physical dimensions... the display size jump to the X was huge).
I would give it some time to see if you can get used to it, because it's looking like the XS will be the smaller of the options for now (unless you go to the iPhone 8). Personally I would give it more time because I think the advantages of the larger OLED display and dual camera are worth it. Now when I pick up my wife's iPhone 6 it feels a bit small to me, but the main thing I notice is the weight difference. The newer models are heavier, but in my opinion that actually makes it easier to hold onto for some reason.
Having written all this I'm not sure if I could comfortably go bigger than the X/XS. The size of my iPhone X feels like my limit, so I hope they never get rid of the 5.8 inch model. I'm sure many feel the same about the iPhone 6/7/8 size.