I'm a big fan of zeolite cat litter and the litter box system with absorption pee pads beneath. I've tried all the things over the years. I hate clay especially.

Despite the initially high upfront cost to get started, I think it's cheaper long term. Even more so because I recycle the zeolite pellets by rinsing them in a big bin instead of throwing them out and buying more. I dry them out then stir in baking soda. It's a porous mineral formed into pellets, doesn't break down just gets dirty over time. You lose some over time of course, lodged in turds and kicked out, fodder for the vacuum, but it's so cheap and way cleaner. The two cats aren't tracking that heavy pellet all over the house like clumping clay or urine soaked wood pellets that disintegrate into pee mulch. Ew.

The pee pads aren't very green of me so maybe next step is figuring out an alternative absorption medium to put in the tray beneath the pellets.

So I'm not recommending any brands because they'd all hate me for not being wasteful and fully replacing pellets every month like their bags instruct. Zeolite is zeolite, buy the cheapest per KG that day. I'd just say avoid Purina/Tidy Cats brand when possible. They over charge, especially for pee pads.