Changing/Reading Villager Data?

Hi, I am used to Java coding, but not so much to forge.

And even after multiple days of googling, I still struggle.

Right now, I am trying to read (and later modify) villager data. The idea is to be able to reset the last level of the villager, including exp and trades.

Right now I am struggling to understand how to read the data, so I get the trades, level and exp.

What I have found: with

entity.getEntityData().getAll();

I get data, but I haven't found any information about what the entry means (only numbers for 1 to 18, while 18 is "VillagerData").

Side question: Is there a way to directly get the "VillagerData" without a "foreach"?

Okay, there I have "VillagerData", but according to this

1.18.2 VillagerData

I can get and set level and profession, but I don't see trades and exp.

Any attempt to get "CompundTag" like

CompoundTag test = entity.getEntityData();

does not work.

How can I get the data so I can modify it?

I am using forge-1.19.2 43.2.0.

Chees