Law keeps getting repeated as someone worthy of 3 billion during his fight with Teach. Oda just values Shanks much more right now, so he gave him a hypetool. Luffy had no contribution in beating BM while Kid/Law damaged Kaido. So Luffy never carried their accomplishment even if he’s the real top-tier threat. Is his bounty donwplayed based on his strength? Yes, he should be higher because he 1v1’d Kaido. Realistically, Kid/Law are still at least 2 bill+, no 2 conventional commanders would ever push a top-tier that far.