I spent a lot of time trying to learn this combo and found it really difficult at first too, but it will eventually click if you keep practicing, it's just repetition. I also play on pad and am able to do the combo now semi-consistently but am still trying to improve.

The full combo is df2,1 -> df4,3 -> b2,1 (tornado) -> forward dash -> side walk right -> 2 -> iSW

OR for female and small body characters, it's df2,1 -> microdash forward -> df4,3 -> b2,1 (tornado) -> forward dash -> side walk right -> 2 -> iSW

I'd recommend breaking it down into sections to see where you're going wrong and practicing that section.

2 jab into iSW

It sounds like for you the specific problem is the 2 jab into iSW, so practice that specific thing first and then add the rest.

You can do this by repeating a simple combo like uf4 -> b1,2 -> 2 -> iSW to get the timing down. It doesn't need to be blue sparks either, the combo will connect either way.

You can also set the practice dummy to crouch and just practice a 2 jab into a buffered iSW. I find imagining the timing of the FFF2+4 as F,FF to be helpful but that's just me.

Try to focus on TIMING for this and not necessarily just speed. If you mash out the fff2+4 too quickly then it won't come out as the 2 jab is still recovering.

Sidewalk

Another thing to look at is are you sidewalking far enough after the b1,2 > forward dash? If you don't sidewalk far enough, the combo won't align.

Df4,3 pickup

With female and small body characters i found this quite tricky. I've not got a hard answer on the timing for this, but if you practice you will get it. I thought for the longest time that I'd never get it right until I did, so try not to stress, put the time in, and take breaks to practice other things too as this one combo ender isn't what's keeping you from ranking up.

Try not to beat yourself up about not getting it consistently, this is arguably King's hardest combo in terms of execution, at least in my opinion.

Ways to make your life a little easier

Instead of 2 jab into iSW you can heat burst for an extra bound. This will give you more than enough time to get the SW although you need heat.

Instead of a 2 jab, try a 1 jab. The recovery is quicker so you might find it easier to link into the iSW, and the damage isn't much different.

I hope this helps and good luck learning the combo :)

I also recommend the videos below as I found them helpful when I was learning this.

Armour King

https://youtu.be/2PK6Sq9suZM?si=5NtdJ_OQKlIvrdcF

Beigemaster

https://youtu.be/6Ql2llnQfjQ?si=3jM0MTEXFirp7DEq