I got Kontakt working halfway okay on Linux Mint. I'll try to scrounge up what I did to get it running. Please remind me if you don't hear back from me.
But tbh, I don't use it much, because even on macOS, I found it sluggish. YMMV though, so I'll try to be helpful soon.
If need be, you may find some free/cheap alternatives to NI instruments in DecentSampler.
This was the video that helped me get it running. https://www.youtube.com/watch?v=iF9kf1oj-UU
I also referenced this thread. https://linuxmusicians.com/viewtopic.php?p=166531