The cam has taken a massive hit it is surface hardened and it can perhaps been a threaded screw or so by the looks of it
I would look at the other side . and look for a small screw somewhere for damage.
And the cam bearings I have had going out
I replace them
The sound can be as mentioned excessive play small end conrod
Valve stem play those have tight tolerances stock
A picture of pistons skirts can give an indication ( if they are out )
The other side of the cam lobe looks fine, it's just that one spot, and the bearing are also in great shape, and seem to be tight. I am replacing the exhaust valve guides, what i thought was damage on the valves just ended up being built up carbon, which im assuming could have caused the play in the guides. I will get a picture of the Piston skirts tonight when I get home from work.