DFs don't grant "Specific" Material Stats, the User becomes embodiment of that Power & He can grow it Stronger,
It's not like Doku Doku No Mi grants you Power of a Specific Poison, it makes you able to create any Poison or Venom or Toxin you want,
Mr. 1's DF isn't Steel Steel No Mi, it turns him into a Blade-Human, so He can get as Strong as a Blade can get, He is a walking Meito but instead of One Blade, He has Infinite.
Ofc, He didn't reach his Full Potential yet, but we can't use the Argument of "This is Stronger than Steel so it should counter Daz", also people confuse between Zoro couldn't Cut Steel, and Zoro couldn't deal with Steel, what He was trying to learn was Cutting Steel directly like He does with weaker Materials, but it doesn't mean He can't damage Steel using other Methods such applying a great force on it or piercing it & damaging it,
Zoro tried a Powerful Multi-Piercing Attack, He tried to break his Stance with Oni Giri followed by Full Might of Tora Gari, He tried to get so close & use a guillotine-like Attack on his Neck, He tried to clash & hit him multiple times in succession, nothing worked!
Daz is also Physically much Stronger than Kimmimaro & He can unleash countless cuts at same time with an insane range, not to mention, He isn't summoning Blades, He is turning into them, so his shapeshifting & close combat threat is very high, not to mention how He can make those Blades spin to the point Zoro's Meito could have been destroyed if fight continued,
Daz takes this.