If you have an iPhone or iPad, this app should do the same that an rk002 would:
I’m not suggesting it as a replacement, but to try this method out and see if you’d be happy with it.
I’ve used this method with an rk006 (same poly feature as the rk002 built in). I can vouch that it’s an okay poly replacement. Personally, with a Digitakt, though, I’d rather sample a chord to a single track. Or check out the single cycle chord pack: Cycle Chord Pack for Sampler
No affiliation, I just own and have used it with success. There’s also a thread on it: Cycle Chord Pack