According to this 24/7 scouting report Keuter's NFL comparison is Leighton Vander Esch.
https://247sports.com/Player/Ben-Kueter-46118691/
The Cowboys drafted Vander Esch in the 1st round, pick 19. His rookie deal was for 4 years, $11.84 million, fully guaranteed. He then signed another 2 year deal worth $8 million ($5 million guaranteed).
So if the comparison is accurate and he has a career like Vander Esch (who has had injury problems which is why his extension is "only" for $8 million) he's still looking at about $15 million guaranteed.
I'm guessing that would be about $14.5 million more than he would make lifetime if he stuck to collegiate/freestyle wrestling.