There is another way to establish varying note lengths with SEQ3 - set the sequencer to pass through the clock, clock the sequencer with an LFO square wave, and use one of the CV channels to modulate the pulse width, and the step trigger to reset the LFO. The SEQ3 trigger then becomes varying length gates to drive your ADSR. A pulse width of 25% is a quarter note, 50% a half note, 75% a dotted half note, etc. A pulse width of 100% (actually only goes to 99%) is a whole note, but the 1% gap prevents tied notes across multiple steps. But this can be overcome by using a low pass filter as a slew limiter to prevent the 1% dip from triggering the ADSR at the transition to the next step.
I posted a video using this technique:
Check the video description for links to the patch, which includes an explanation for how it works. The video also is a demo of how to create a 32 step sequencer using 5 SEQ3 modules.
If you are sticking with VCV Fundamental modules for now, then you might want to check out VCV Fundamental Constructs, where I have a bunch of VCV selections using only Fundamental modules to implement all kinds of useful techniques.
Finally, the VCV documentation is incomplete and/or out-of-date for the Fundamental modules. I’ve attempted to document a few of them:
Proposed documentation for the VCV Fundamental SEQ 3 module
Proposed updated documentation for the V2 VCV Fundamental Random module