Block storage? When you create your persistent volume claim, you can specify an accessMode. "readWriteOnce" will target block storage of the storageClass, "readWriteMany" will use file.

You can also choose something specific like a mounted hostVolume which is not provider specifc.

Cutting edge stuff like NVMe-oF is even possible, the CSI ecosystem is very active. https://github.com/spdk/spdk-csi