Villagers & Wandering traders don't take jobs or have trades.
When overriding vanilla Villagers & Wandering Traders, they do not have trades and villagers don't accept jobs.
Override Villagers & Wandering Traders in VanillaMobs.yml
VILLAGER:
Health: 20
Options:
HasTrade: true
PreventRenaming: false
PreventTransformation: false
WANDERING_TRADER:
Health: 20
Options:
HasTrade: true
PreventRenaming: false
Reload/Restart, try to trade.
Players are unable to trade or make villagers accept jobs.