The best stat for this type of comparison is 5v5 GF/60 and GA/60 with a large sample. It allows for uneven ice time due to injuries but requires context. In this case we only have two top right wingers and two top centers so it a reasonable comparison but not perfect.
Last 3 full seasons 5v5:
| | GP | TOI | GF | GA | +/- | GF/60 | GA/60 | GF% |
Auston Matthews | Mitchell Marner | 205 | 1808 | 120 | 74 | 46 | 3.98 | 2.46 | 61.86 |
John Tavares | Mitchell Marner | 215 | 889 | 45 | 29 | 16 | 3.04 | 1.96 | 60.81 |
Auston Matthews | William Nylander | 227 | 829 | 50 | 33 | 17 | 3.62 | 2.39 | 60.24 |
John Tavares | William Nylander | 237 | 1559 | 72 | 83 | -11 | 2.77 | 3.19 | 46.45 |
Matthews and Marner are superstars.
Marner with JT is as good as Nylander with Matthews.
Nylander with JT is a disaster.