Patch Request: Fluke - Atom Bomb (Bass)

Hi everyone, I’m trying to both replicate and understand how to program a similar sequence of this classic track by Fluke.

Right at the start.

The the first few notes sound rounded, than comes the note that sticks out.

How would you replicate something like this? In Serum, or primer?

A friend of mine says, it’s a Korg MS-20, though it sounds more like a 303.

Is that an LFO attached to the cutoff, that is opening the filter like that? Or a mod matrix?

I graduated from Syntorial long ago, but when I open my eyes, I’m still only in Saigon.