To be fair I don't think OP needs one iPad let alone two. This is a thread about what'd be nice to have. I've tried a relative's Kindle (multiple versions, multiple books read) and didn't like the experience. I also have an iPhone 13 Pro Max and the Mini 6 is a much more pleasant reading (and gaming) experience for me, to the point where I probably wouldn't entirely hate having a smaller phone in the future. It feels much lighter and nice amount of screen for longer reading, bigger but easy to hold in one (small) hand.
I personally wouldn't pick an Air and an iPad Pro, too similar in size and I don't see myself holding the Air in bed a lot. I haven't been bothered at all by the mini screen. I'm basically switching from the 4th 12.9 Pro to the Air, gave the pro to a family member, but my Mini stays. I eyed it for ages thinking it'd be silly to have that and a bigger iPad and a phone. yes of course it's frivolous but I use it constantly, and actually take it out unlike my pro