Let's keep things in perspective.
Reg Freeman - Third Division North Champions (1951)
Andy Smailes - Highest Ever Finish - Third Place, Second Division (1955)
Tom Johnston - League Cup runners-up (1961)
Ronnie Moore - Four seasons in the second tier
Steve Evans - Kept Rotherham in the Championship
Neil Warnock - Kept Rotherham in the Championship
Paul Warne - Three promotions and three relegations (first relegation mostly not his fault, second promotion mainly due to Covid).