Hi, I share with interested in midi curves these alternatives for Windows and Linux (Wine).
The first is midiCurve from insertPizHere (some of his plugins are ported to Linux for @falktx) and can modify Velocity, CC, Channel Pressure, and Poly Aftertouch, another plugin called midiPitchbendCurve exists too. In the capture, this runs with wine and linvst (airwave, carla and yabridge works on these too) and run in Ardour with one of these. Linvst consumption is huge, the plugin is programmed with Juce but is 32 bits and VST2, but the code is available in google too.
For insert and edit points works with mouse buttons.
The other is a free tiny host for windows, but the developers claim to run on Linux through wine and add a couple of midi filters like velocity transformation and come with some presets. This uses a .exe file to use a windows dll like standalone app.