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.