Unfortunately Dragonball is filled with hyperboles showing how "powerful" an attack is and it really depends on what you mean by the most powerful moves.
One instance is how Cell said he gathered enough energy to destroy the solar system.
"Forget the Earth, I can destroy the entire Solar System with my
First, Super Perfect Cell stores up a huge amount of energy as he
prepares a Super Kamehameha. He then brings his hands forward and
fires a blast that has enough power to wipe out an entire Solar
Essentially yes Destructo Disk is pretty powerful because it can cut through anything but that pales in comparison to the power of others in the Dragonball Universe that supposedly have planet busting / galaxy busting / universe busting moves.
In fact other characters have improved versions of Krillin's Signature attack such as Frieza's Death Saucer because it can actually follow a target.
Death Saucer is an improved version of the Destructo Disk created by
Frieza and which has the ability to follow a certain target around.
Cell can use both versions; Krillin as well as everyone else are
shocked when Cell unveils this technique, and Krillin even questions
whether Cell improved the attack.
Also note according to the wikia The Destructo Disk doesn't always work.
Unlike energy blasts, the Destructo Disk can actually injure enemies
many times the wielder's power level, such as being able to cut off
Frieza's tail when energy blasts from the likes of Vegeta and Gohan
proved ineffective. In the anime only, Krillin uses it once on Perfect
Cell, with the disk shattering on Cell's neck, being too tough for
even Krillin's ki disk's "edge" to cut.
Even though it's not canon Amond deflects Krillin's disk with his own technique as well.
The Crusher Corps. commander, Amond, uses an unnamed disk-launching
technique where he spins on himself before launching a razor-sharp
disk of energy. He used this technique to deflect Krillin's Destructo
Disk in The Tree of Might.
The overall answer is no Destruco Disk is not the most powerful move in the Dragonball universe because there are attacks that are MUCH more powerful.