It looks like the freezing issue is fixed with the latest Decker version - so finally I can check this out! The demo songs sound really cool!!! This is great!
This probably isn't the best place to ask me this, since that guide does have its own comments section, but it looks like it's due to this issue. https://itch.io/t/5229926/decker-makes-constant-clicking-sound-on-one-of-my-comp...
Short version: it is a bug in certain versions of SDL2. Fixing it may be up to your distro upgrading to a version that fixes the bug.