While there's a lot of season to go, Jannik Sinner is on pace for his third season in a row with a 90 Win% or better. He would join a rather exclusive club of only X players to have three seasons in a row with 90W%:
Connors: 1974-76 (also 1978)
Borg: 1977-80
Lendl: 1985-87 (also 1982, 1989)
Federer: 2004-06 (also 2017)
As you can see, Borg had four seasons in a row.
There have only been 25 seasons in the Open Era, 26 if you round up Andy Murray's 89.7 in 2016.
Here are all players with at least one season:
5 seasons: Lendl
4 seasons: Connors, Borg, Federer
2 seasons: Nadal, Djokovic, Sinner
1 season: Vilas, McEnroe
Anyhow, I think this gives a sense of Sinner's high level of consistent dominance.