(Helping with dependency issues is difficult and cumbersome. I never quite understand why things fail.
In this case, you have installed versions of samplv1 and Qtractor that already work with librubberband3. You installed them from the official MX repository. Therefore, the repository must have librubberband3... Well, it doesn't, it's giving you an error. Why???
I think you now have all the pieces to be able to update everything.)
Now that I know that one is good (thaks Rui), you can also find it here.
https://launchpad.net/~rncbc/+archive/ubuntu/libs-noble/+packages
https://launchpad.net/~rncbc/+archive/ubuntu/libs-noble/+files/librubberband3_4.0.0-18.1_amd64.deb
(Helping with dependency issues is difficult and cumbersome. I never quite understand why things fail.
In this case, you have installed versions of samplv1 and Qtractor that already work with librubberband3. You installed them from the official MX repository. Therefore, the repository must have librubberband3... Well, it doesn't, it's giving you an error. Why???
I think you now have all the pieces to be able to update everything.)