I'm not "snowballing" his abilities, and you are the one who is neglecting what is shown on the profiles. Doflamingo being able to one-shot characters at or above 377MT is clearly superior Meliodas being able to do something similar by slicing apart an arm of a baseline 7-A character.
- "At least 7-A+" > "7-A". Even factoring in the Demon Mark making him "obliterate opponents who previously went even with him", he is no where near Doflamingo's equal in power in the first place.
Doflamingo's thread attacks are by nature are incredibly hard to detect due to how thin they are, as only individuals who have known Doflamingo long enough (Law, who then informed the Straw-Hats of his ability) or have competent Kenbunshoku Haki (Sanji/Luffy) have been able to even notice his attacks, but this clearly isn't enough since both Luffy and Sanji were unable to figure out why their bodies stopped moving suddenly after they were grabbed by the threads.
- Meliodas' only notable sensory abilities are based on detecting magic.
Meliodas can not break Doflamingo's threads. He lacks the AP and Lifting Strength to do so. It took Bound-Man Luffy to break them, but even he wasn't able to do it consistently despite being above Doflamingo in physical strength.
- Meanwhile, the Black Knight for some reason is the only string construct made by Doflamingo consistently torn apart by fodder and mid/high tiers alike.
Busoshoku Haki just goes on to amp Doflamingo's attack and defensive capabilities, widening the gap in stats even more.
I also fail to see how Meliodas would be able to deal with Doflamingo's Awakening since that turns the entire battle-ground into threads that Doflamingo has full control over.
Literally all Doflamingo would have to do is his standard tactic of defensive evasion -> grapple with threads -> wound. Meliodas will regen, so Doflamingo will just keep slicing him apart until he either figures out how to kill him, or Meliodas just goes incapacitated. Even if Meliodas found some way to break free from the threads, he has no reliable method of overpowering Doflamingo, and worst-case, he makes Doffy pop Awakening and the fight is practically over since everything around them will just be Doflamingo's ability.