Q: Will this command "sudo chflags 0 /Volumes/*" delete my data?

It won’t delete your data, but that should be backed up anyway.

If a connected drive(other than a network server) doesn’t show up in the Disk Utility, the problem is in hardware, and no Terminal command or other software can resolve the issue.

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To run sudo commands the user must first of all enable root user account , once entered in root user account correct sudo command must be executed .

An apple articles are there : Mac OS X: sudo command requires a non-blank admin password - Apple Support

                                           : Enabling and using the "root" user in OS X - Apple Support

It won’t, and enabling root isn’t part of using sudo.

(143482)

To run sudo commands the user must first of all enable root user account

That is NOT correct, and is not beneficial in any way. Do not do this.