If it were me,
@soapSuds , I would isolate the one thing I liked best about this soap and then try to replicate that one piece, then perhaps add others.
So if you like the semi-swirls, go for ITP swirl.
If you like the lines, do a spin swirl.
(Both of these will have swirl all the way through).
If you like the white on bottom and colour on top, pour a white base, then start spin swirl or ITP swirl on top. You may have a bit of bleed-through (although TD [or clay] in the base would thicken it, I think), but it would be easier than doing it in two discrete steps.
AFAIK, all of these techniques will require thin trace though, and spin swirl takes a long time to get through and you need to stay super thin all the way through, so I'd go with just one approach for now.
TBH, I find the white base weird. Having seen plenty of aurora borealis, I can say that a more realistic base colour would be black, not white! (Better contrast with the neon, too).
Anyway, go do it quick so we can see the results, please!