Animelover5487 said:
Dabura wasn't surpressed against Gohan,
His reactions in comparison to Gohan say differently. Dabura was calm and confident throughout the entire fight, not even breaking a sweat, and didn't even seem surprised when his sword got broken, whereas Gohan was taking things entirely seriously and clearly being worn down. Dabura was also confident in facing Gohan again despite the latter having healed up to at least the level when they fought and even referred to him as trash and Gohan even meditating on Goku's words to get angry as though it's a necessity to win, something very difficult to swallow when just accounting for his rusty skills and stamina.
Moreover, their reactions to Boo are quite telling.
There's also a comparison between their reactions to Boo. Gohan refers to initial Boo's Ki as monstrous and clearly notes how bad the situation is, even noting it's not hopeless if he can use all his strength. Meanwhile, whereas Dabura finds Boo nothing noteworthy until he powers up despite Dabura still having some form of Ki sensing when he could sense the Dragon Team hiding and distinguish the three highest Kis, and even mocked their attempts to suppress their presence.
For what supplementary material is worth, you also have both the Super manga and Z anime validating this. The former shows Dabura taking a kick from SS2 Trunks fairly well despite Base Trunks swinging the Z-Sword far easier than Boo Arc Gohan or Goku could initially do in base as well as his blade clashing evenly with it, with the Z anime having Trunks noted Dabura's Ki increased when he fought Boo. Overall, there seems to be a lot more supporting Dabura holding back against Gohan than the contrary, of which I'll go into:
Q: "Why didn't Dabura damage Gohan enough?"
A: Dabura was already characterised as finding enjoyment in toying with weaker fighters and not completely following Babidi's orders, both evidenced by him disappointed Pui Pui may leave nothing for him. His reactions during the fight suggest this was such a case, Dabura having his fun before getting a chance to seriously damage him, and it's not as though that was difficult with how much Gohan's stamina was dropping.
Q: "Why did Dabura resort to the sword and spit?"
A: Gohan was expendable as an energy resource. Considering Babidi initially estimated three guys weaker than Pui Pui can fill up the meter, one such as Gohan was expendable when he still had two more to draw from and knew at least one had over 3,000 Kiri. Dabura was clearly annoyed at Gohan's arrogance too, so he may have wanted to use either method to show how green he was.
Q: "What about the Daizenshuu saying their battle was even, or the Dragon Books saying Dabura had inferior power?"
A: Their battle wasn't an even one when Gohan was constantly losing ground and never gained a solid advantage on Dabura. The anime version of the fight added a lot of filler to make Gohan have a better performance and, even then, it was later revealed Dabura was still hiding some power.
CG SS2 Gohan was stronger than SPC.
Dragon Books disagrees.
Gohan was stronger at the end of the Kamehameha struggle, but that was after bringing his power to new heights.
The latter is further supported by Boo Arc statements such as Goku and Vegeta's comments on a hypothetical enraged Gohan, as well as CG Gohan being implied to be simultaneously not much weaker than Goku/Majin Vegeta yet still someone Pre-Majin Vegeta could potentially beat.