So, just obatin the whisperer any way you want to, use it like you would use any other. However, after that, the villager will refuse to trade anything, until you destroy and redeploy his working station, but that also resets his trades, making this whisperer impossible to properly use.

Wunderreich version is 3.0.18, minecraft version is 1.19.2

I'm having the same issue, but with the mending imprinted whisperer. When I reroll the Librarian's trades, their offers go blank and durability is used. Then, If I back out, I can no longer interact with them, unless I break their station. I'm on version 1.20.1 of Minecraft and 6.0.4 of Wunderreich.