I got nodes that seem to shut themselves down when encountering high iowait’s

I saw something like that before. It’s usually happens if the docker image got corrupted for any reason (my raspberry pi sometimes got it). But it suggests problems with the disk, where docker is storing images (in case of my raspberry - it’s microSD card).
I would recommend to stop and remove all storagenode containers and remove the image, then pull it again.
After that try to start your nodes and check logs.