Vivo X300 and Oppo X9S Pro are both very compact(6.3") and still pack great cameras and insane battery life thanks to the Silicone carbide batteries.

I don’t think you realise how massive the two phones just suggested are: https://phonesized.com/compare/#1863,2767,2760

(For reference, I would really like something a little bit smaller than the Mini, but there’s nothing remotely modern that exists.)

Correct, they are still bigger than the mini. But compared to what seems to be the industry standard of 6.8" they are positively miniature.

They’re considerably bigger than even the normal non-Mini iPhone. They’re only just smaller than the iPhone 17 Pro Max: https://phonesized.com/compare/#1863,2767,2760,2738,2736

You're comparing wrong models though? X9 and X300 Pro are both much larger than the phones I mentioned.

(I've just noticed you also used wrong models in your original comparison - while both phones are larger than the mini, the difference isn't as large as your link suggests)

The iPhone is normal phone size width and depth, but it's meaningfully shorter than just about everything else. It doesn't sound like much on paper but I've always found it adds up once in a pocket. (All dimensions height x width x depth, in mm, rounded up to the nearest mm)

* iPhone Mini: 132 x 72 x 8 (https://support.apple.com/en-gb/111877)

These two alternatives are noticeably larger:

* Vivo X300: 151 × 72 × 8 (https://www.vivo.com/in/products/param/x300)

* Oppo X9S: 157 x 74 x 8 (https://www.oppo.com/en/smartphones/series-find-x/find-x9s/s...)

In fact, they're more like the size of the full size iPhone, which, if you're sticking with your iPhone Mini because the iPhone is annoyingly large, means they're too large.

* iPhone 17: 150 x 72 x 8 (https://www.apple.com/uk/iphone-17/specs/)

They're also bigger than the base Samsung S26. They're not small even in comparison to other Android phones.

Base S26 is almost exactly the same size though?

https://m.gsmarena.com/compare.php3?idPhone1=14456&idPhone2=...

The X9S Pro is half a milimeter taller.

Sorry, I was looking at the non-pro variant by mistake.

This is totally not "vaguely modern name-brand" but I've been using the e-ink Mudita Kompakt and it's more or less the same size, but a bit thicker. It's Android but no Google Play Services but probably doesn't tick your box

Same, on a 12 Mini right now, been looking for phones (any OS) that has similar size for maybe the last 2 years, and while some Xperia models have come close to the right size, everyone is still aiming for "bigger === better" it seems. Can't wait for the pendulum to switch back to smaller phones again...