being he is so young.... per a Binky, I would make sure that you know his hunger cues.
"Sucking" on hands/fingers, can be a cue that he needs to feed.
He is only 4 weeks old.
And newborns feed a lot. At 3 weeks, it was a growth-spurt, for example. Newborns have growth-spurts every 3 weeks, then at 3 months, 6 months, 9 months and every 3 months.
A binky, can sometimes be confused with a baby's need to feed.
And babies need to feed on-demand. Which can be every 1 hour or 2 hours or 3 hours or so. They also cluster-feed. Which means they will need to feed even every hour. And this is normal.
He is also too young to sleep train.
Babies, also "suck" on fingers etc., while in the womb. It is an instinct.