For our first-born I bought a cheap digital fish weighing scale (1 gram resolution, I think I paid 1-2 USD for it) from Taiwan because I found it incredible that the midwives/nursing staff was basing their assessments on either low-resolution analogue scales or a single readout from a digital scale. You can weigh the baby once or twice each day and track whether they're gaining weight or not.
But don't fret - overthinking this can lead to everything turning sour and frightening, even if the baby is fine. You don't want to be frightened, you want both baby and mother to relax and get some sleep so they are motivated to try again.
We've always had babies that were relatively awake the first week - that means relatively more grumpy that there isn't yet enough milk. Last time, my wife gave the baby a little bit of the breast milk substitution you can buy to get through that period. That really helped. Baby happy and asleep for longer and the mother didn't have a baby chewing up her nipples all the time.
But don't fret - overthinking this can lead to everything turning sour and frightening, even if the baby is fine. You don't want to be frightened, you want both baby and mother to relax and get some sleep so they are motivated to try again.
We've always had babies that were relatively awake the first week - that means relatively more grumpy that there isn't yet enough milk. Last time, my wife gave the baby a little bit of the breast milk substitution you can buy to get through that period. That really helped. Baby happy and asleep for longer and the mother didn't have a baby chewing up her nipples all the time.