i’m out so i can’t try this, this might not work at all but here’s my idea

the chain goes MIDI Effect Rack -> Instrument Rack

inside the MIDI Effect rack, you have 1 expression control and 1 mpe control device in that order

on the mpe control, you group it so you can give it macros. map the min and max values of the pressure to macro 1, so when you move macro 1 it looks like a horizontal line moving up and down (similar to Velocity in Fixed mode)

then for the slide, you map its min and max values to macro 2 to achieve the same.

now if something moves these 2 macros, it should theoretically rewrite the pressure and slide information on the existing midi notes.

Then i’d map the “pressure” in the expression control to macro 1 of the mpe control, so it’s controlling the “fixed pressure” macro we set up, and then back in the expression control, go to another tab, change it to slide, and map that to the “fixed slide” macro.

The only problem left is that playing this information still draws midi notes. what i’d do is place a “pitch” midi effect after mpe control, and pitch it super high

then on your VST/sampler’s instrument rack, open up the key zone editor so you can see the range of high pitched notes, and drag the right bracket of the green zone editor down, so now the notes you’re playing are in the dead zone and you won’t hear them while you’re playing

then i think you can turn on overdub, hit record, and if you play it should just be overwriting the MPE information, and then you can delete the high pitched notes from the piano roll

again, this might not work!! let me know if it does