One distro that keeps coming up in conversations like this is CachyOS. It kind of makes sense why it has blown up over the last year: Their whole goal is squeezing out more speed everywhere they can, and that includes disk IO.
They ship with the right scheduler defaults for NVMe, they have IO scheduler rules that automatically pick the best option for each device type, and they even have their own scheduler called ADIOS that’s tuned for modern multi-queue setups. So they’re clearly thinking about performance at the block layer, not just desktop responsiveness.
I haven’t tested CachyOS for raw disk IO myself yet. I’ve only clicked around the desktop to get a feel for it.
It does look like a solid pick for anyone who’s trying to get better throughput or wants a distro that focuses heavily on tuning and tweaking for faster IO.