You can define it however you want. Top 20 attempts to find builds with top Damage that also have good Survivability (for the most part any build can be tweaked to be either very tanky or damaging but not both at the same time). It tries to do it precisely. You cannot really do it without speedrunning some content (if you just measure how deep SR you can reach for example) / pushing the timer because then you cannot measure Damage well enough. Also if you play the game, measure bulids and even speedrun in a different way, which you probably do, then I think it’s normal if you have different impressions.
This is again, to measure builds more precisely. If you push builds to the limits / get good at them, then you measure them better with each other.
Dunno, maybe it’s just about different goals:
- as much damage as possible while surviving (well) in some specific content (Top 20)
vs - as deep SR as possible while having decent damage (many other players)