One thing I see is that you don't seem to have much rod side/side clearance on that rod pair.
Another thing I see is that the chamfer on the rod looks like it's been possibly running against the fillet on the crank rod journal.
If it's not those two things, then it could be a cracked rod journal. Normally, when you can find no other smoking gun and you have a spun rod bearing with the main bearing that feeds it looking good, then the crank could have developed a crack on that rod journal. When that happens, it bleeds out and you will have less
oil getting to the bearing.