russian steps are really a version of intervals; eg: 30s of effort then 30s of recovery, then 60/60, 90/90, 120/120, 90/90, etc.
But when climbing hard climbs I do 5 revs seated and then 5 standing, then 10/10, 15/15, 20/20, 25/25, 20/20, 15/15…… and repeat as long as necessary until you’re there.
It’s harder work climbing standing, particularly if like today your standing is very low cadence, but concentrating on getting through the intervals is better than thinking about how hard it is.
As for climbing seated. It is supposedly easier as you don’t have to support your body weight at the same time, but I don’t have the same leg strength in the seated muscle groups as I do standing (that SS background again) hence if I want to climb ‘fast’ then it’s standing and full gas, sitting and spinning is for saving energy. And sometimes it’s all I have to be able to keep the pedals moving…..