Kees
This thread becomes a bit complex, so let me try to come to a conclusion.

When you want a better chisel then the current western offerings you can do two things.

Buy some Japanese ones.

Buy some CPM 3V, hacksaw, file ang grind a chisel shape. Then find a heat treater who likes to experiment a bit. Find the best heat treating schedule. Then go out to source some flat bits of cast iron and buy the neccessary diamokd grits. Finish the chisel.

That's about it, isn't it?
In the near future the LV PM V11 is another choice.