Ciro Santilli Worked on Ubuntu 20.10.
The UI is a bit too buggy to bear.
How to unsplit, can't find on shotcut 21.05.01: forum.shotcut.org/t/is-it-possible-to-unsplit/1466/2
Background noise reduction: couldn't easily find out how, especially with automatic profile detected based on a selected region as mentioned at audacity profile-based background noise removal: