Are there strategies for content creators to prove their location?

With a looming snap election in Germany, there is revived discussion in Europe and Germany on regulating internet platforms and social media to make foreign election interference and misinformation campaigns harder to carry out.

Regulating or moderating digital discourse to combat misinformation is notoriously difficult on many levels, but one model that has seen some adoption is offering additional information and context to consumers of digital information. For example, YouTube displays contextual information under videos that discuss certain topics, and Twitter/X has the community notes feature.

To mitigate foreign misinformation, a potentially powerful piece of context in the run-up to elections could be whether or not the content was posted from a device located within the European Union (EU). For the sake of argument, assume that the goal is to offer social media users the option to verify that their social media post was sent from a device physically located within the EU. Unverified content could appear as before but could be labeled as "may not originate from inside the EU", much like email clients may display "sender is not part of your organization".

Independent of the merits of such a feature in helping to mitigate foreign misinformation, my technical question is whether you see a practical way to implement a protocol that allows end users of digital platforms to prove that they are physically present within the EU without revealing their actual location to anyone.

The verification would not establish where the post content comes from since it may be relayed to the posting device through the internet, but verified posting should require some physical 'last-mile' EU hardware. In other words, foreign actors intent on pretending to be European would have to acquire/hack a significant number of in-EU devices to relay their messages from overseas. A rate limit on posts per verified device could further increase the cost of verified content posts from foreign imposters.

The solutions can assume that social media companies, ISP providers, or what have you, are cooperating to a reasonable degree to implement a solution. To illustrate this, consider that during the COVID pandemic, the EU with help from Apple and Google, implemented a tracing protocol that used Bluetooth proximity technology to detect nearby devices of users while preserving their privacy [1]. Could an approach like this be used to establish plausible physical EU presence of a device that would be hard or costly to spoof for a foreign actor? What are protocols that would make content infiltration a little harder than jumping on a VPN with ChatGPT from somewhere in the world?

In other words, are there practical strategies for opt-in, "zero-knowledge" proofs that your location is within a relevant jurisdiction?

[1] https://commission.europa.eu/strategy-and-policy/coronavirus-response/travel-during-coronavirus-pandemic/contact-tracing-and-warning-apps-during-covid-19_en