ARM Mac Recovery Mode - Show available HD space in Terminal

I'm trying to get familiar with showing specific HW information from the Recovery Mode terminal for audit purposes. I'm not too savvy with recovery mode commands for terminal. I'm unable to show internal storage total disk space & available disk space, which would "show" the laptop has been wiped. Reason being, Terminal allows me to run commands to show serial number, and current date by running:

ioreg -l | grep IOPlatformSerialNumber

followed by the date command while it's connected to a network. If I could show the total & available disk space it would help tremendously. ARM Macs don't allow diskUtil eraseDisk for /dev/disk0 so can't prove a wiped disk in that way anymore. Any ideas would be appreciated.