Please read what I wrote before you try to claim I’m contradicting myself.
Disengage doesn’t make them more tanky because the person they disengaged from can walk the same distance the rogue did and hit them again. Rogues do not get a speed boost without a cost in actions that negates the effectiveness of their speed boost.
Dex save does not apply to weapon attacks or to Scorching Ray, which uses attack rolls.
Three attacks are more likely to hit than one attack. If the rogue misses one attack, they’ve missed all their attacks. If one ray that comes from Scorching Ray misses, there are several others that might stand a chance.
My comment, and every comment that came after, was about how neither damage nor tankiness is better than tactical planning. Which you STILL haven’t responded to! Don’t try to claim it’s about something I specifically stated, in every single comment, it’s not about!