The sweet spot for minutes is still about 60, so you should be aiming to get them around that a week. The only player that might now make sense from the ones that you posted was player 2. In my experience he probably should have stayed in 9 GS, but that's just bad luck. Anything over 70 minutes a week is too much unless you are training GS. 68 is just a tad bit too many. My guess is that player 3 went from 9 GS to low 8 GS and player 4 went from 9 GS to high 8 GS, same with player 2.
I'd like to see the examples of the 28 minutes/118 minutes players but my guess is that they train GS and got lucky. If you do that on a consistent basis, however it will not work. Still aim for 60 minutes a week.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs