I like the idea in the edit more honestly. My only concern is that detecting a URL in the text part might be hard. Especially with a malicious user there could be invisible Unicode characters.
It'd also be nice if the link preview had a setting to put it under the paragraph with the link instead of at the bottom. A bit unweildy for some longer posts/comments.
https://www.gps.gov/systems/gps/performance/accuracy/
Bottom two sections are most relevant