But for a few different reasons I ended up just getting my wife an S22 (non plus) and then inherited her S20 (non plus), which has a very similar form factor.
Definitely felt the OPs frustration in looking for compact Android phones. They just plain don't exist.
The Sony seems to be the best alternative though I have no idea of the software quality.
Pixel 5 - 144.7 x 70.4 x 8 mm
Samsung S22 - 146 x 70.6 x 7.6 mm
Zenfone 8 - 148 x 68.5 x 8.9 mm (could be higher thanks to narrower body)
Xiaomi 12X - 152.7 x 69.9 x 8.2 mm
Samsung S21 - 151.7 x 71.2 x 7.9 mm
Sony doesn't produce phones, but remote controls. Their software is nice clean, but their camera is pretty bad, might as well buy Zenfone 8 if you don't mind camera.
I imagine few who have used one would ever be able to say this with a straight face. I never met an iPhone user who believed me when I told them all the photos I was showing them were taken with an Xperia XZc (1 and 2, respectively) and that's with every single one of them. There may be half a dozen compact smartphones that really compare to the XZ2c. Sony just gave up on them because the herd loves their phablets so much.
I am also a current owner of the Zenphone 8 and its camera is also decent. If it's really important that you be able to snap the best photos possible, though, they've been developing these discrete camera things for over a century (and the best of them will likely continue to outperform any general purpose device for the foreseeable future).
SHIFT5me - 141,5 mm x 71 mm x 9 mm
There's really nothing small about any of the Androids.
I have an Xperia 10 II (or something like that, the slimmest Android device I could find back in early 2021). The back cover is cracked all over, to the point I sometimes get cuts on my fingers. Two of the corners have dents.
The back camera that takes the actual photo is several degrees off (like 10 or 15°) from whatever is used for the preview. Works perfectly in all the other ways. Probably isn't waterproof any more, but I never needed that before, either.
Unfortunately, it looks like it won't be sold in the US. Does it support US LTE bands so I can import it at least?
A headphone jack is much more useful for me personally than 5G, so I happily saved the money.
I dislike Apple for a lot of things but in this duopoly the size of a phone is such a fundamental characteristic that you’re out of options anyway.
I think most of the people are “swiper users” — the “content consumers” — so they want big phones and OEMs are simply making what the near 100% majority (yup!) wants.
It is, however, probably not a great idea to use a device that hasn't had a security update for several years.
Even if you were using a custom ROM and trusted that it was correctly patched (which is a big if) then there's hardware exploits on the Snapdragon 820, and I imagine there are probably similar on the Exynos 8890. Some of these can't be mitigated by software.
Hopefully by then there is something available which continues the form factor. 4a has been the perfect successor to the Nexus 4, it's a little taller but other than that has practically the same footprint.
With the 6a moving in a different direction (eg: removing the headphone jack) I'm just hoping someone else comes along as a spiritual successor for the Pixel Xa-series.