"Let's address this. No, Giratina has never beat down an idea without a physical form. Every single fight between members of the Creation Trio in the franchise, be it anime, manga, or games, has been between their physical forms. If there is an instance I'm not remembering, then please show me, but I don't ever recall the abstract selves of the Creation Trio doing battle."
Firstly, keep in mind that I still don't buy that Chara's an idea, and I didn't respond because I simply got lazy. Secondly, it's remiss to assume that they can't hit each other at all in their true forms. Chara's profile in general takes bigger leaps in logic than this.
Also, show me once Chara being untouchable in any sense of the word.
"Second, the gap between Giratina and Chara is being blown way the hell out of proportion. The sheer power Giratina is assumed to have is coming from fan theory that makes its "countless" seem way higher than it is, but it is countless all the same. There is zero quantifiable difference between the power levels of these two aside from "one is probably stronger than the other". That isn't even remotely the case for Samurai Jack and Goku. I invite you to check the Attack Potency page and look at the actual, quantifiable difference between Large Building level and baseline Universe level. Now please show me the quantifiable difference between Chara and Giratina that mirrors this, because I'm pretty sure we don't have one. Also, "It's too big"? Where is the Distortion World ever shown to be bigger than the size of a multiverse?"
If you could show me Undertale having undeniable evidence of having more than a few universes (honestly, they should be 2-C), because Resets being any more than that instead of creation of new universes being much more of a "fan theory", I'd take this with more of a grain of salt. But until you can, yes, the difference between the two is indeed astronomical.