Modern? According to gsmarena, literally the only Android phone with at least Android 12 with a height less than 135mm (the iPhone 13 mini is 131.5mm high, acco

Modern? According to gsmarena, literally the only Android phone with at least Android 12 with a height less than 135mm (the iPhone 13 mini is 131.5mm high, according to the same site) is the Cubot J20. Which looks adorable, but is a 60€ Aliexpress device and probably not what you seek. If you are okay with older phones, there is the Sony Xperia XZ2 compact, which is even supported by several custom roms and would then run Android 13. Or there are foldables of course, like the Samsung Flip. That's at least small some of the time, and there are some alternatives where the small screen on the outside is big enough to be usable, like the new razr+.