Nap times

My 4 week old sleeps allll day, wakes up for feedings, I change her diaper, and is awake for about 20 ish minutes afterwards, then she goes back to sleep. How long are your newborns naps?? Is it normal that my little ones last between 3-4 hours 😭 i just feel like she’s not awake enough through the day to do tummy time or for me to entertain her. I’m still trying to figure out her “schedule” but she pretty much does her own thing and it varies allll the time.