It would be very useful to be able to import a file having each destination/mask on a line, to complement the Add Route dialog in the Connections - Networking - Routing.
I think that in most cases the IP Version, Gateway and Metric will stay the same and are anyways easy to be edited later. But adding a dozen destinations and masks manually is an error-prone and tedious task.
One option you could consider to bulk add routes is copy-pasting the routes into the advanced commands text field for the connection. The syntax is “route <gateway (optional)>” for IPv4, and “route-ipv6 / <gateway (optional)>” for IPv6. For example:
Thank you for being interested in keeping up with the latest news from us! Please double-check your email address below and then click the Subscribe button.