how can i delete a protected resource?

You have to first do an update that removes the protection bit. So it's a two step process.

what if i don’t have the code anymore which created the resource in the first place?

Then you would need to manually remove the bit with

pulumi stack export

/ remove protected bit /

pulumi stack import

prior to the destroy. It's more or less intentional that

protect

makes it hard to delete. But https://github.com/pulumi/pulumi/issues/1909 would help make the workaround a single command instead of the export/import dance.

ok thanks for the clarification 🙂