I'm trying to refactor my code so that my networks are moved from their current project / stack into a new project specifically for networking, as it's going to be referenced more often. I've tried adding an alias, but it keeps saying it wants to create new resources? Anyone got any ideas?

You could use import in your new stack instead? https://www.pulumi.com/docs/guides/adopting/import/

Once I've imported it, can I remove that reference from the other project without it being deleted when "pulumi up"?

You'll have to do some state "magic" I'd assume. Export the state to local file, remove the resource, and references, then import the state again. https://www.pulumi.com/docs/reference/cli/pulumi_stack_export/

there’s a command

pulumi state delete

to do that without messing with the state manually

Have done, thank you

yes, help for this command has an example

I've upvoted the issue, and recommended that perhaps a recipe of steps in how to move resources between stacks would be very helpful to newbies like myself

Oh cool, didn't know about the

state delete