The only other things I might want to have a look at before pulling it out of the car for teardown, is the intermediate shaft, timing cover and cam thrust /retention/button setup.

You say it has a hydraulic roller.

If a person were to install a cam button and force fit the timing cover on without creating thrust clearance, in other words if they bind up the cam between the block and the timing cover,
the timing gear-to-block interface could be eating each other up and could potentially make that much metal.

If it has a billet steel camshaft and gear with a stock intermediate shaft, those could be eating each other up as well.

It has to come out and be torn down regardless....... as that metal has been circulating and has probably done some damage....but it might provide worthwhile info to have a look at those areas.