Regarding smell, consider trying a raw meat diet. I use Purrform (UK) but there are similar in other countries. I was a sceptic, but since converting to raw meat diet, there is almost no poop smell except when I feed too many treats. Living in a small London flat, this has been a game changer. Obviously there are risks with raw meat diets and they aren't the cheapest. Do your research, understand the potential issues…
https://www.zooplus.co.uk/magazine/cat/cat-nutrition/barf-ca...
>What is BARF?
>The term 'BARF' describes so-called 'biologically appropriate raw food'. This feeding method is appropriate for the key reason that cats are carnivorous by nature. Raw food gives them just that – lots of fresh meat. In contrast to cooking your own cat food, BARF portions are given out raw and are not cooked or seared beforehand. However, this has also led to criticism of raw food, which is mostly unhealthy for humans and can lead to stomach upsets and intolerances. Does the same not also apply for cats?