The following applies only to the declarative pipeline.

For the moment, there is only the name option for the unstash step.

I would like to have an extra option for the unstash step like ignoreFailures=false|true, by default on false to be backward compatible.

This extra option helps a lot when testing or using when conditionals on the pipeline stages, as there might be a stage before the unstash that actually does the stash, but the code in the step after the unstash can fallback to defaults if it cannot find the unstashed file.

It would be okay if, for example, the whole build can be made unstable if the unstash fails.

For the moment there is no way to continue it in the declarative pipeline (as the try/catch) is not supported.