The unread badge is green, which stands out more than our blue - maybe we can find a tone of blue that stands out more
or go back to green, we had that before. another blue tone - not sure. i find already the existing one too close to the “verified” color when scrolling really fast and only skimming over things (we changed to blue as every os had a different color, and we just picked one, blue was the one from desktop)
I just noticed that in WhatsApp I never have this problem of not finding unread chats
i agree. for me personally, the reason is that i have vastly more chats in Delta as in Whatsapp. also, there is at least one situation where unread chats are not sort up, i had that recently with the “wrong info message” - these kind of things are hard to find later
but also whatsapp has a function to show only unread chats, it is a little hidden when you tap on “search”, you have options to set some filters:
when selecting, this becomes a “filter tag”, this is nice, however, for Delta Chat, regarding our current resources, this seems a bit out of scope on all UIs.
but maybe we can start with core-only thing: we could offer entering a filter in the form read:no
(or so, similar to github) - that could be just typed, and at least experienced users can use it.
as a simple subsequent step, to make things better discoverable, there could be a menu or so beside the search field, that just prepends that to the search field. in a later step, these filters could also be shown as “filter tags”.
advantage would be that the functionality would be available on all UI without the need to do anything iniitially effort - and things would be similar to what other advances searches have.
just an idea 
whatever, we do, however, i think, the “discover unread only” should not be in the primary UI (mainmenu eg. would be tempting, but i think, it is a too rare function and i would not clutter things there), i think, it is okay if it is a bit hidden and is discovered at some later point (when you search for it as you really have 500 chats). i think, it should somehow be related to “search”.