I just clicked the link above for the first time since I originally explored this concept, and I see this update:
2. Eligibility in news
Publishers no longer need to submit their site to be eligible for the Google News app and website. Publishers are automatically considered for Top stories or the News tab of Search. They just need to produce high-quality content and comply with Google News content policies.
Reading this, I recommend you simply submit your Webflow site to be considered as a Publication here: https://publishercenter.google.com/publications
It looks relatively straightforward from here… just note what Google mentions in the above article: " Important: Submitting a feed or a URL through the Publisher Center does not guarantee surfacing or ranking in Google News."