Definitely make sure it's set to LP / LP filter.
One thing about the Matriarch is that it's a stereo synth, but only after the mixer module. This means that the oscillators are essentially mono unless you patch to change it. The Rev2 has a Pan Spread parameter that puts an oscillator in each ear. That can contribute greatly to the perceived fatness. I don't have a Rev2 so I can't confirm that this parameter has been set wide for an init preset.
If you want to do this with the Matriarch you can, but you will need to avoid using its mixer. The Matriarch mixer is special in that it overdrives the waveforms in the same way that old Moog Modulars did, allowing for particular tones, but it has a mono output. What you would do to change this is bypass the mixer by running the output of 2 oscillators into a submix for each stereo side and then patch them into the VCF1/2 inputs directly. You can try doing this with a combination of the Matriarch's dual mults (and attenuverters if you want to control the relative levels of 1 of the 2 oscillators). This may give you some of what you're after.
Since it's a semi-modular synth you can actually replace the mixer with something Eurorack compatible. I have the Intellijel Quad VCA, which works well for this purpose, but there are plenty of others, too. I can patch the oscs to it, mix them at the levels I want, then bring them back in at the filter. It's really endless when you begin to branch out to a little bit of eurorack. I suggest figuring out what you're after then building a small companion rack for the Matrarch to expand it in ways you desire. It's not cheap, though. That's the burn of modular.
So in summary, try this as a starting point:
Osc1, osc2 to left mult
Mult to attenuverter 1 input
Attenuverter 1 output to VCF 1 in
Osc3, 4 to right mult
Multi to attenuverter 3 input
Attenuverter 3 output to VCF 2 in
Attenuverters up to taste, filter freqs slightly off from center to taste
Set filter to LP / LP, spacing at noon
Alternatively if you want to control relative levels of the two oscillators instead of the overall levels:
Osc 1 to attenuverter 1 in
Atten 1 out to mult 1
Osc 2 to mult 1
Mult 1 out to VCF 1 in
Osc 3 to attenuverter 3 in
Atten 3 out to mult 2
Osc 4 to mult 2
Mult 2 out to VCF 2 in
Same settings.
Also remember you're comparing a monosynth to a polysynth, so keep that in mind of course when comparing playstyle.
Also when looking at eurorack modules for stereo expansion, something like the Make Noise X-Pan or similar that lets you control the stereo placement could be better than a normal mixer with submixes like the Quad VCA (which is similar to the native patch above putting things panned hard L/R).