The speculation and rumors will soon change because the big reveal is not too far distant. This video from Sandbox News/Airpower with Alex Hollings tells the story. The below video is 18:52 in length.
From Sandboxx, January 21, 2022
Back in 2009, Boeing’s Silent Eagle aimed to make the world’s most prolific air superiority fighter into something more by injecting stealth into the F-15’s legendary DNA. The result may have been the most broadly capable F-15 the world had ever seen, delivered just in time to compete with what would become a foreign sales powerhouse, the F-35 Joint Strike Fighter.
Here, below, in a 17:21 long video, is a summary of that project and its potential outcome for the USAF.