FitBit tracking men and women differently?

[svengali_sven]

Has anyone noticed using Fitbit if they track men and women differently?
My partner and I are both the same age 58 and similar levels of fitness.
We eat well and rise at the same time and go to bed at the same time.
We both bought out FitBit Ionics the same time - May 2020 and we can do exactly the same exercise on the same setting and come out with completely different numbers.
Cases in point:
Sleep: I get vastly poorer sleep results than my partner.
She always gets much better sleep results, even if she has less sleep than I do.
(She's a shift worker and can get called out, while I get to stay in bed, but she can still have a better score)
Excercise: When we do exactly the same workout, my result shows much much higher calories burned (often more than twice as many) and often many more steps taken (sometimes 2-3 times more steps taken).
Is FitBit making assumptions about gender and ageing?
Am I as a male expected to get less quality sleep and my partner expected to burn fewer calories than I?
Is this a gender and age biased thing or is there something else going on?
Has anyone else had this experience?

[JohnnyRow]

Exercise - weight and heart rate are big factors in calorie burn.  Do you both weight the same?  Do your heart rates look similar through the workouts?

Sleep - look at the components of sleep score: time asleep, deep & REM, restoration.

[svengali_sven]

Thank you for your thoughts.
No, we don't weigh the same. I am 6'4" and about 90kg and my partner is 5'9" and about 80kg.
She has a consistently lower heart rate while working out - both her average and maximum.
I though, have a much lower resting heart rate.
We do look at the respective sleep components and I generally get more REM and more Deep than she, but she still gets a better overall score.