Some of your old proprietary plugins and hardware might work in Linux through a compatibility layer like WINE. Or it might work out of box, no software required. Or it might not work no matter what. It’ll be a bit of a crapshoot for each one.
I will say that JACK and Pipewire may make some of your hardware unnecessary, especially if your using it to get around Windows limited audio routing capabilities.
And of course MIDI stuff will generally work without issues. It’s MIDI.
I’ve never played with that Maschine mk3 so I couldn’t tell you how or it it will function.