Yes. The HomeRunner property detail page supports a short one-liner underneath the property title. It is a useful place for the two or three things you would otherwise be tempted to cram into the title, the way you have to on Airbnb.
Keep the subtitle to a single line. It is not the place for a descriptive paragraph, which belongs in the description.
Where the subtitle comes from. Both the title and the subtitle can be sourced from any Guesty field. A dedicated custom field is the cleaner approach, because it makes the intent explicit and keeps the value from drifting when someone edits your OTA title.