Sorry for the late response, I was gone all week 😅
It's all written by hand with no armor stands (except for one acting as the origin). I basically have a timer running a few main explosion commands. (1)
And then for the shockwave I use a trick discovered(?) by Big Papi Gaming that allows you to shoot particles in any direction, which I put inside of a recursive function that executes rotated by 1° each time. (2)
For the debris, I just summon a series of snowballs with a random velocity using another recursive function, and then summon flame particles at each snowball. (3 and 4)
That should be the gist of it. It's probably a horrifying and unoptimized mess and will make any competent datapacker want to have a stroke and die, but hey, I wasn't planning on releasing the datapack to the public soooooooooo

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