Ten week old sleeping 20 hours a day?

My ten week old sleeps all. day. long. I would feel confidant this was a growth spurt, but she has done it since the day she was born. She’s barely awake. When she is awake she is alert, curious, active and smiley.

Bedtime is eight PM. She’ll sleep until 4AM, have a bottle, go right back to sleep. Wakes up at 9:30AM, feeds, awake for about a half hour then back to sleep until about 2PM. Up for about an hour. Back to sleep until about six, up for two hours. Crashes hard at 8PM. Repeat. Same schedule every day and has been consistent for weeks. Every now and then she’ll even sleep through those few awake times.

Anyone who comes to visit has some comment about how this isn’t normal and it’s causing me to worry excessively.

She has a wonderful pediatrician who isn’t worried about her, so I’m really just looking for some personal experience from others who might have babies that did the same thing. Did they grow out of it? Did they hit all their milestones? First time mom and I overthink everything.