So, how should I best approach DDD? Remember, I only ask because I respect your opinion.
Well...it's tough. Spacing always comes first, his grab range is obnoxious so make sure you don't get too close.
I think jabs are absolutely useless against Dedede. I think he can grab you no matter what you do even if you only do the first jab.
I'll usually short hop airdodge his waddle dees and either forward B or paralyzer shot on the way down. You only need one solid hit in order to start up a combo. You're going to want to do whatever you can to get him airborne. Good players shield both of these a big majority of the time but if you keep your distance with them it's worth it for when they finally hit.
I also abuse D-smash a good deal when I'm at the furthest range for it. It pushes him back enough so that he can't grab you if he shields it. It hits him a lot when he rolls too, and he's one of the easiest characters to combo out of D-smashes. You can up-b him afterwards and drag him back down. Even if they tech this you can tech chase grab if you're fast enough. You can also do double d-smash to grab, and DDD can be grab released chain grabbed so this is a good opportunity to go for. And if you d-smash from the furthest distance possible I would follow up with a JCed Upsmash since that's basically the only thing that will reach and it will get him in the air. Also watch out for his up-tilt, that will punish d-smash spam.