|||ALL CREDIT GOES TO J4kefradz FOR DESIGN|||
Here is a zombie villager converter, you can use this to easily convert your villagers to zombie villagers and back for cheaper trades. I took the design from J4kefradz's video on YouTube and made it into a Litematica schematic for easy building.
Send villager in by rail by pressing the first button. Once the zombie has 'killed' the villager and it becomes a zombie villager, press the second button to send it to the end of the converter. There, you can convert it back with a potion of weakness and feed it a golden apple.