4A-GE valve shim disintegrated

[DaLanZhu]

On my 86 a valve shim on the intake valves disintegrated. The shim broke into 5 pieces, luckily I was able to find all of them.
The lifter is damaged, and stuck in the cylinder head. The valve is stuck open.








Initially I was thinking about replacing the cylinder head entirely, but looking at the damage I think what might work is to grind off the damaged aluminum in the cylinder head using a Proxxon tool, polish it and install with new camshaft, lifter and shim.
What are your thoughts on this? I am not super familiar with all these grinding sockets for the Proxxon, any tool recommendation to minimize further damage?