I like the vibe of this patch. Kind of rhodes-esque. Try this:
Filter: Low Pass 24 dB, with a little Drive, and Key Tracking enabled. Bring the Cutoff down until you get the desired roundness.
Amp Envelope: Create a piano shape by bringing the Sustain down and setting the Decay and Release to medium long, around 1.2 seconds.
Velocity: Route it to volume, and play the higher repeating note louder than the lower notes. Also, if your synth allows, route the velocity to the Amp Envelope attack as well. Set the Attack to around 120 ms, and then set the Velocity modulation amount to a negative value that brings the Attack down to zero. Now, the harder notes (higher velocity) will have a sharper attack transient, and softer notes will have a softer attack transient.
NOTE: if you can’t route velocity to amp attack, instead create a second copy of the patch for the lower notes, and set their amp attack to around 120 ms.