we currently don’t have an official way to make rootfs read-only, and I think the issue is that why is it so easy for your file system to get corrupted with sudden power off?
Like, we are plugging and unplugging the power cable of our devices during boot everyday, and we have never seen the same issue. Maybe you should try with a different SD card/NVMe SSD?
Technically, you could use OverlayFS, but I’m not sure if anyone has actually got this to work. If it does work, then you probably would need the l4t_initrd_flash.sh (perhaps with modification). I know in the past people have had a lot of issues getting OverlayFS to work.