Interesting thought.
First let’s save others from having to respond, because they’re unhappy with the reliability of a used Rise. Obviously you’ve already thought that through.
The Rise is really about MPE control. That is its forte. If your target devices aren’t MPE it will have less power.
In that price range consider a new or used Hydrasynth Explorer. It can run as a controller with both MPE, and poly-aftertouch. It has fewer dimensions than the Rise, but has good flexibility setting up various custom controls for MIDI CC and CV output. Plus there is a synth built in as an extra.