the problem is more what the 1st Gate draws from
The 1st Gate is a 5x multiplier because it allows you to draw 100% of your own physical power vs the 20% you can normally use.
DMS Kakashi isn't really his own power; it's Obito basically possessing Kakashi's body to temporarily let him use his Six Path's chakra.
1st Gate DMS Kakashi would need to be using his personal hidden reserves of physical power to amp himself 5x the Six Paths Chakra that Obito is letting him temporarily use, but that doesn't make any sense.
That's basically saying Normal, Sharinganless, Kakashi's 80% reserved chakra is 5x greater than Ghost Obito's Six Path power
would be helpful ty