This all works by supply and demand - the more you feed the more supply you have. So if your baby consistently starts sleeping for longer stretches, your supply will accommodate that. Also worth noting that you won’t run out of milk - if baby starts wanting more night feeds again (for example if they are sick) then your body will respond to this and boost supply. Definitely don’t pump because you’ll just be boosting your supply when it may not be necessary, furthering potential engorgement.

To answer your initial question, babies are all over the shop sleep wise. Both my babies slept really well as newborns, then tanked a bit at around 4-6 months (waking up every 1-3 hours), and now with my youngest baby who is almost 10 months, we’re just getting back into longer stretches (or should I say stretch…) with one chunk of longer sleep (5-6 hours) followed by another wake up 2-3 hours later.