I just don't get fancy chisels, I use a modern Stanley set, and even a heavy Tesco one on hard African timbers, does me fine.
You likely know this already, that the Egyptians used copper chisels on stone.
Having a guess at this, so apologies if I'm not correct with your issue,
but I wouldn't expect any chisel to hold up to 'abuse'
which to me sounds like what's happening, (if they are indeed sharp)
What I mean by abuse is sinking the bevel (full depth of it or close to it)
in something hard and not clear pine, without having somewhere for the waste to go.
So if cutting a mortise, starting out small chops until you have some sort of a hole made, and if chopping waste of a tenon or dovetail.
Have a look at the term 'tenting'
Basically it means not undercutting the work, but the opposite to stop the chisel sinking too deep in the work (which likely would make you cut well past your line anyway)
Or not starting out making deep chops vertically.
You will be able to chisel deeper if there is less force from the waste side of the bevel.
Tom