Sorry if typos I am typing from my phone btw (in case of autocorrect)
I'm not saying you automatically lose because you jumped lol, I'm saying though that means your DD could still use work (or your DD just didn't work for something obvious, like you DD'ed and ran off the edge or something). It means that you could still use some work in either spacing your DD distances or positioning yourself to maximize your DD potential. All I'm saying is that if you jump, you're not necessarily in a bad spot at all, but it still means you probably could've done more with your DD that you just didn't do. I will admit though, sometimes DDing isn't always the answer. Fox's DD is really ****ing good though, so getting used to abusing it can take you very far.
That solution isn't bad, but it's a mixup, and probably one that should be spared for rare instances. If the opponent has reason to believe you'll do it often, that sort of dash attack is pretty trivial to punish: shielding flats out beat it, shielding can be done even from a dash, and getting shield-grabbed as Fox is quite often GGs.
Mix it up with DD grabs, DD aerials, and maybe some pivot tilts for max effect. Also, in Fox dittos against a Fox who liked dash-dancing a lot, I just run in and dtilt in the middle of his DD. It got me a good amount of success. This is from two people who aren't high-level Fox players though, so take from that what you will.