in addition to all the other suggestions:
6 weeks is a growth-spurt period in an infant. Every 3 weeks is a growth-spurt period in an infant. And then at 3 months, 6 months, 9 months and so on, in a baby.
I would, make sure you are producing enough milk, and that she is latching on properly. If not, she will not be getting enough intake... and the infant will then be hungry, and not be satiated to sleep well. If going though a growth spurt, and intake is not keeping pace with the baby, then there is a baby that will be hungry. And always feed on-demand... not by a 'schedule.'
I say this because this happened to many friends of mine. Once the baby did get enough intake, their baby slept much better.
Also, is there a reason you "keep her awake for about 1 hour after she's eaten...or until she gets sleepy or fussy?" Once a baby gets "fussy"... it usually means they are ALREADY over-tired... and over-tired babies/children actually do not sleep well, nor fall asleep well, and they wake more.
So, by then the window of opportunity, has passed. Because they are then over-tired. Already.
Most infants, if full/had enough intake, do get sleepy at the breast and/or fall asleep and they fall off the breast. Indicating they are full/satiated.
But your baby sleeps well at night... so that's great!
She is really young... and stimuli can get them over-stimulated real easy in an infant too. Sounds/texture/smells/even a bath is an 'activity' for an infant. Again she is real young.. and they do not yet have a "pattern" of naps. And once they do get into a pattern... then there are the usual sleep tweaks which comes with developmental changes. So it sort of never ends. Their sleep 'patterns' always changes....
But, my suggestion would be, to not keep her awake on purpose, after feeding.
And, try putting her in the crib, to nap/sleep... after feeding. Before she gets fussy.
Also, at certain growth-spurt junctures, an infant even "cluster feeds" and this means they will feed even every.single.hour. This means they are increasing their intake needs... and need it. So always... feed on-demand. My kids had GINORMOUS appetites and sometimes it seemed they were needing to feed constantly... but they grew like weeds and my milk increased per their needs.
And you can try putting her in a sleep sack. Many infants like that 'cozy' feel... like being in the womb.
all the best,