How do I remove 'untitled' partition from terminal or disk utility?

I've been trying for ages but can't work out how to completely remove these two Untitled volumes(?). I've tried remove, erase, and the minus button in Disk Utility and the commands in terminal don’t make sense or seem to work . Please find attached images. I have Catalina OS

disk utility screenshot

list from disk utility


Ok. Nothing on disk3 needs changing yet, so all the CS commands are dangerous or ineffective

What happens when you issue:

diskutil eraseVolume free free disk0s4
diskutil eraseVolume free free disk0s3

Also, please use care, if you delete the wrong 0s4 you will lose everything. Do you have a backup and internet to reinstall if you or I make a mistake?