In RL it’s obvious within minutes whether new/newish fathers are doing a fair share, from how couples look and seem.
Night parenting should be shared IMO (not necessarily 50/50, but much, much fairer split than 90/10), unless one of the parents has health issues that mean sleep is even more important, or one of a small number of jobs where sleep deprivation could be a safety risk.
Apart from a small subset of jobs involving safety risks, fathers working FT don’t need more sleep for their health and wellbeing, and ability to perform their role, than a mother on mat leave parenting a baby.
Unless a baby/toddler sleeps very well. the mum doing more than is fair can lead to exhaustion and associated health (and safety) risks.
I experienced this with DC1, who slept terribly until age 2. DH didn’t do a fair share at night, I did 90% or more. After 9 months or so I became unwell, physically and mentally. Also had a minor injury and a some scary near misses due to fatigue, eg boiling water and the baby, crossing roads.
Meanwhile he was sprightly, socialising and doing ten mile runs! We changed things with DC2, who slept better, and even then and sharing the work more fairly we were both very tired, but OK.