I actually considered NetBSD for an old 32 bit box yesterday, so I'm somewhat wise to this world. My first experience with ramdisk operating systems was Puppy Linux back in the early 2010s. Ultimately I'm probably going with OpenBSD for that box.
But, NetBSD ISOs are much heavier than TCL ISOs, and so while I'm sure there's a way to get just what I want working in diskless mode, I'm not confident I will have any RAM to run what I actually want to run on top of it.
Puppy Linux was pretty sweet back then, I used it for a Gecko machine for a few years until I got a vastly more powerful 'flat' netbook that arrived after those. It was a pretty nice gadget, though one had to have small and/or flexible fingers or the keyboard would have been a pain.
But, NetBSD ISOs are much heavier than TCL ISOs, and so while I'm sure there's a way to get just what I want working in diskless mode, I'm not confident I will have any RAM to run what I actually want to run on top of it.