DDP has heart, but he's also not a Tony Ferguson or Merab where he's just going to melt his opponents cardio with activity. He's gotten taken down by Till, Whittaker, and Brunson. Till/Whittaker he just got out from there, and they never shot again. Against Brunson he sort of just accepted position and tried for a comeback in the 2nd round which was what he did.
I just don't see DDP as a workhorse that gasses his opponents out besides the pressure he puts on. He's really dangerous as the fight goes on, but I think only Khamzat can gas himself out going for a finish he can't get. Also I think DDP will gas out trying to stop 1st round Khamzat.