Why are you running bench start and bench run-tests? any custom module or customization also part of this erpnext instance you are experiencing issues with?
bench backup and restore helps to go back to a state at which backup was taken or move site from one server to another.
Also set Third Party Backups so you can relax!
You can take backups for selective sites with command
$ bench --site <sitename> backup --with-files
for Importing / Exporting Data for selective doctypes use Data Import Tool.
Data Import Tool is NOT Backup
AND
Hire an Expert if you do not have idea and does not wish to have blunder. from https://community.erpnext.com/service-providers