I guess you have all modules to get a huge kick.
FLD6 and crb4n are well for it.
Maybe you need to find the right compression or a better sidechaining.
I guess one general approach is:
adiditional wavefolding on the kick + modulated reverb/delay on the rumble + the right sidechaining + compression
I use befaco percall. I do wavefolding on a nice vco and send it to channel 1 of percall to get a instant kick. I use the multed copy of the kick without wavefolding and send it through a delay/reverb (mimeophon) to create rumble. I modulate the delay and reverb with synced lfos. - I send the rumble into channel 2 of percall to get it ducked against the kick. Addiotional i can modulate the strength cv of percall to get rhytmical chopped beats. End of chain is mscl for compression.
I use bastl waver as a drum bus. I send the kick of SSF Ultra Kick (which offers a finished kick + dynamics) trough Channel 1 on bastl waver to add some wavefolding/distortion. I send my Rumble from BIA or other modules through a delay/reverb and modulate it with lfos (mimeophon), then I send it in channel 3 of waver - to use it´s internal vca to sidechain it against the kick with the sidchain-envelope from Ultra Kick. With waver I can modulate the wavefolding and also break it rhytmically with the break cv, to get nice effects. End of chain is mscl for compression.
Greetings
Chris