For those interested I have a list of year by year leaders with relative ratings for All-Season data (RS + PS) as one on of the columns where that data was available. The first sheet is actually focused on the top player by ORtg & DRtg going back to '96-97, and that's not mentioned so far, so let me package some stuff here to go along with the
actual spreadsheet.
Among players who have led the league in ORtg while playing >50% of their team's minutes (so only the top guy each season), here are the ones with the biggest rORtg (based on bkref):
1. Steve Nash (Phx) '04-05 +13.9
2. Steph Curry (GS) '16-17 +13.2
3. Chris Paul (LAC) '14-15 +11.4
4. Steve Nash (Phx) '06-07 +11.3
(tie) Steph Curry (GS) '15-16 +11.3
(tie) Nikola Jokic (Den) '22-23 +11.3 (so far)
7. Dirk Nowitzki (Dal) '03-04 +11.0
8. James Harden (OKC) '11-12 +10.8
9. Steve Nash (Phx) '09-10 +10.6
10. Kawhi Leonard (LAC) '20-21 +10.5
For rDTG:
1. David Robinson (SAS) '98-99 -11.5
2. Jaren Jackson Sr. (SAS) '97-98 -10.4
3. Tim Duncan (SAS) '03-04 -10.1
4. Kendrick Perkins (BOS) '07-08 -9.9
(tie) Giannis Antetokounmpo (MIL) '19-20 -9.9
6. Alonzo Mourning (MIA) '96-97 -9.4
7. David Robinson (SAS) '00-01 -8.6
(tie) Kawhi Leonard (SAS) '15-16 -8.6
9. Kevin Garnett (BOS) '10-11 -8.5
10. Bruce Bowen (SAS) '06-07 -8.4
And the leaders in terms of leading in the most years by these standards:
ORtg
1. Steve Nash (PHX) 7 times
2. John Stockton (UTA) 3
(tie) Dirk Nowitzki (DAL) 3
(tie) Chris Paul (LAC) 3
5. Steph Curry (GS) 2
(tie) Kevin Durant (GS) 2
DRtg
1. Tim Duncan (SAS) 3 times
2. David Robinson (SAS) 2
(tie) Kevin Garnett (BOS) 2
(tie) Draymond Green (GS) 2
(tie) Giannis Antetokounmpo (MIL) 2