How many hours is high? Who has the highest ?

Recently bought a 17 GCV with 76900 miles and 3346 hours . Coming to 22.9 mph or an additional 110,418 miles ( 33 x 3346)

I knew it was a fleet vehicle for the first 40k miles but didn't realize it had high hours. My dumb *** was thinking it was highway mileage when i was purchasing.

How screwed am i? BOTH head gaskets just got replaced by the dealer for a p0300 code. lol thats what got me going down this rabbit hole.