My villager (1.16.4) doesn't want to look for his job even though he has light, lecturer and a bed sometimes it works after minutes in creative on another world but it works
So, they only look for jobs during working hours
If he already has a job and not a new addiction, then you may have traded with him.
And villagers in green robes are "useless" who are generally not looking for jobs
Do you have a work block for him? Without a work block, he won't get a job.
Examples:
Blacksmith's table: blacksmith
Smoker: butcher
Lectern: librarian
… Etc
Did you dismantle his old work block?
As you can see in the top left, he has no job and no green robe.
Yes I have
Yes I have
Then you just have to wait…