I'm not sure "The Doomed City" by the Strugatski Brothers counts, but I'll put it here anyway. It all happens in some weird place where people from different places and periods in time are part of some kind of experiment. Societys are being formed and destroyed and outside the city lie the ruins of places where it seems past experiments have taken place. Or perhaps parts of the current experiment. So there is definitely a postapocalyptic vibe there, but it's most certainly not the usual kind of such a story and it's more Kafka than straight out Sci-Fi.
And the Strugatski's "Roadside Picnic" is also somewhat postapocaliptic, people might know it as the inspiration for the movie Stalker and the unrelated game.

Station 11.

Excellent new spin on the total collapse and then fragile re-building of society after a super-flu.

https://www.goodreads.com/book/show/...station-eleven

The Death of Grass ,1956.No blade of Grass is a movie adaptation of that book.

I didn't see any John Wyndham novels on your list, Chula. His novels feel a little dated by today's standards, but in a good way, I think. They are short and polite to the reader: they tell a story from start to finish and don't load the text up with flashbacks or complex mythologies that have to be worked out. Many of his books were post-apocalyptic, or apocalypse-as-it-happens, which I hope is equally appealing. Although they are usually found in the science fiction category, the focus is always on the humanity of the characters, not the technology.

The Day of the Triffids, The Midwich Cuckoos (= the film, Village of the Damned), The Chrysalids and The Kraken Wakes are his best, and for your convenience, I have put them in order of bestness, at least imo.