Is this for rebar tying ?
In some places, concreter’s nippers are used instead of pliers for tying off rebar, and the nippers are usually available in longer lengths than typical ironworker’s pliers, which should increase leverage, and ease of cutting.
Knipex makes Chrome Plated nippers, which may increase durability a bit, but I don’t know how much it would help.
I don’t think anyone has been making replacement blade nippers or pliers for decades, outside of small ones.
I think nowadays, you’re just meant to purchase a new pair of pliers when the cutters get dull.
Depending on how quickly the cutters dull, you might try purchasing a bunch of different brands, to see if any really are that much more durable.
Crescent manufactures two separate “linesman” pliers using compound leverage, but neither have the handle foot, and I don’t know that either would be more durable.