No synth can have multiple patches running at the same time, you will always have to use three instances to get three patches simultaneously.
This shouldn't be a problem: you can just use the routing settings in your daw to make the audio from all three patches go to one place, and one lot of MIDI play all three separate instances at the same time- no expensive extra software needed, it just takes slightly longer to set up.
If you know how to sounddesign half decently you can get very similar results to using multiple copies of the plug by just using any synth with multiple oscillators, but often you are limited because you can't use different filters and FX on the separate oscillators separately. Synthmaster is quite good for this because it has two identical but totally separate layers (each of which is a pretty powerful synth in it's own right), massive, serum and z3ta 2+ are also worth looking into.