I tried a lot but eventually just stick with straw. Everything else was either poisonous, demolishable, or too dusty leading to a lot of sneezing. Or they ate it. Or too expensive.
and especially the last weeks... close my nose a lot

That age where they are outgrowing their brooder.
Towels worked; but I found out I did not actually washed them eventually and just throw them away, and I don't feel like throwing so much towels away every year.
I guess it is a bit personal what works best for you.
I'm not a big cleaner; so I needed an easy system. Spare cage for ducks while changing the straw next to it, big bin for dirty straw right next to it, fresh bale of straw álso right next to it, everything as easy as possible.
Also changing the water system helped a LOT! Since the most dirtyness comes from their water-party's. The water-system is now a baby-chicken water-system that fit's their tiny beaks better, and is now on a seperate elevated plastic plate so all the water will reach the straw less. Because the smell mostly comes from when their poo in straw gets wet. Poo in dry straw is more easy to remove.
I also saw someone getting creative over here, but I can't find the post anymore, that made the water/feeding area and the straw/bedding-area only connected to each other with a gate, a system with two brooders connected, so you don't have to change the whole cage every time after a water-party. The wet-area did not have bedding; so it was more easy to clean with a simple wipe.