Building a workflow can be a long and repetitive process, so when you have something that works, it makes sense to replicate it easily. Here's how to copy actions between workflows.
Copying The Action
Navigate to the Workflow tab inside the Automation section and edit one of your workflows.

Click the three dots next to the first action you want to copy.

Select "Copy Action" to grab just the action, or "Copy All Actions From Here" if you want to duplicate multiple.

Pasting The Action
Head to your target workflow. You can open it in a different tab or use the same tab you're already on.

Hover over the canvas to reveal the plus icon, then click the quick paste button to add your actions.

Validate Pasted Actions before saving the workflow, and you're done. You can easily recreate workflow actions and their customisation, no rebuilding required.