The requirements are <6" display, that's not exactly great. The Zenfone 9 would qualify.

It's way bigger than iPhone 13 mini that is mentioned on that website. It's pretty similar to a non-mini iPhone 13.

I can't sign up for that because they include a bunch of criteria beyond "small" that I, frankly, do not want.

1. They want OLED which has nothing to do with the phone size. I strongly prefer avoiding OLED because I prefer longevity / not having burn-in.

2. Hole punch front camera: I'd like to avoid any sort of notch/punch/deviation from standard rectangularish screens.

3. 2 rear cameras: I don't care. At least this one isn't a bad choice like the others, I just don't care.

and that is in their "must have" section, so I cannot commit my support.

They want a small premium smartphone, and those have been standard features for premium smartphones for a couple of years now. You evidently want to stray further from the premium category, not that there is anything wrong with it -- you make fair arguments.

Wanted to "sign up" there but getting a 404: NOT_FOUND after submitting the form

That seems oddly appropriate.

Sorry about that! Fixed now.