In CB2018, I try to keep my players over 80 endurance and usually have starters between 22 to 32 minutes (out of 40) on court.

Here in Pro, fatigue is much slower and my key players can easily play 40-42 minutes (out of 48) without ever falling below 85. Am I doing something wrong? The most enduring players should play around 36-38 realistically.

What does your sub matrix look like? That could be issue. Also, I use 85 as my out point and get realistic minutes.

I'm not using sub matrix because it takes half an hour to rearrange it after a day-to-day injury. I'm playing the games myself at 9 speed, it also makes my team perform much better. No one is falling below 80 while playing 42 minutes, some not even below 85.

I set my sub matrix using the 'Set by Minutes' option on the rotation tab. I set the starters to 32 and subs to 16 with out-point at 85% and get realistic results.

It also takes only a minute to reset after an injury, if that. You do need to have a subbing plan in mind, however.

It seems to me that it's possible to set starters to 42-44 minutes (out maybe a bit lower, 80) and they will remain fit and effective.

You get realistic minutes if you set the matrix to realistic minutes, but you don't need to and it looks like a serious exploit.

Gary has posted elsewhere that playing too many minutes will wear players down over the course of a season. I have not tried what you are doing, however his intention is that it will result in fatigued players.

Running your players that many minutes for an extended period of time increases the chance of injury as you get later into the season. This is particularly true if you're running high Pace and/or high Defensive Intensity. We've seen ample evidence of that across all versions of DDS in MP leagues. So it might seem like an exploit at first glance, but you're also playing with fire.