Off the top of my head, here's Duck's air bypass route that is p optimal and universal, IIRC, with that DHC tacked on.
- cLK cMK1 cHP jHP HBypass jHK1 MBypass adc jMK2 jHP rejump jLP jHK2 HBypass adc jMPn sLP3 (sLK here would be finnicky IMO) sMPn cMK2 sHP HBypass EKG > Strike
- 12111 dmg @ 1.0 ratio (2v2 test)
and, on Filia...
sLP1 (rest whiffs on her crouching, also, this hits mid, so she blocks it for free) sLK sMPa (scaling is awful now) sMKa (even worse) cHP jLP jMK2 EKG, then quite a delay to DHC to Strike Up The Band to even get it to hit Filia falling to the other side of the screen, and damage varies by as much as 500, easily.
- sLP1 sLK sMPa sMKa cHP jLP jMK2 EKG delay Strike (fullscreen hit)
- 6200~6500 dmg @ 1.0 ratio (2v2 test)
Here's a video comparison for you
@FinestFantasy13 of your combo vs a combo that is maximized for damage and has a proper starter.
And..
Short combos are ok! Until you can maximize on stuff later. You need to learn combos and strings that grow along with your skill level, execution wise. You're not expected to do MAX DAMAGE OPTIMAL COMBOS every time or right off the bat!
But your combo isn't even beginner friendly, IMO, due to the weird DHC you can easily drop. Strike up the band is best when DHC'd into from the ground, if you can help it.
By simplifying your combo..
cLK cMK1 sHP HBypass EKG SSJ does 6681 damage @ 1.0 ratio (2v2 test)
cLK cMK1 sHP HBypass EKG Strike does 9007 damage @ 1.0 ratio (2v2 test)
See, by doing single, hard hitting moves, and not pumping up damage scaling, I can do a simpler combo than yours that does more damage, actually.
The SSJ combo beats your strike combo, and is cheaper, and the strike combo here also beats your strike combo, by over 2k~ more damage.
Good luck! Don't let the game's systems scare you off, they may look slightly intimidating at first, but they're very easy to understand, actually.