Hi Lior,
At this time, the Survey123 URL parameters do not support opening an existing survey in the field app. This has been introduced for the web app; see Survey123 Tricks of the Trade: Editing records in a web form
Can we expect that to become possible in the near future?
You can edit in directly in Collector but of course it would not be a smart form. Are these for repeat visits? If so I always like those to be separate forms.