SPOILERS INSIDE
Love it till the end...which I found was such a cop out. Not only did the boy find people to save him, but it was a family, with a boy (and girl as possible hope for future) and a bloody dog - but then there was the damn beetle...
Would have preferred a more miserable ending myself - would have been much more realistic & keeping with the rest of the film...

That is one interpretation.
A more realistic one would be that they all ended up in the stew pot 10 minutes later, which is entirely likely given that their family unit was weak, vulnerable, indefensible and extremely edible.
The world was dead, and they would be soon too.
The ending was just a little reminder that humanity can exist in the horror too. It did not mean that it would prevail , or that the good guys win. No.
Have you read the book yet?
I really enjoyed this one, to the extent one can be said to have enjoyed a peek into a pretty unrelentingly grim existence. I would have preferred the beetle to have been the sole little (arguable) ray of hope, and agree the dog was rather much even though we were clued in about dogs earlier in the movie.
CK
A more realistic one would be that they all ended up in the stew pot 10 minutes later
no its not. the book is so unremittingly bleak that the little bit of a cheat ending is a welcome relief. cant be arsed seeing the film as it wont even come close to the book

cant be arsed seeing the film as it wont even come close to the book
That is what I was expecting, but I was wrong.

Have yet to see the film, didn't they leave out the "barbeque" scene?
Spoilers for the book
Regarding the final paragraph with the brook trout, is that meant to show what has been destroyed or a glimpse of nature fighting back?

I liked the twist at the end. Did OP get the kid's speech, after his dad stole Omar's clothes? He has to survive, because that's what the story is about. The author didn't send those characters on that journey just so he could torture them for your amusement.