Shotcut currently has no way to properly work with multitrack audio. I mean basic sliders for levels of each track and/or automation/envelopes to vary levels over time.
Technically a DAW supporting basic video can be used, such as for instance Reaper, but to properly edit video a basic control is needed. As I understand, this is on the roadmap.
My suggestion is the following:
-Allow for multitrack audio export: rendering every audio track to a separate file
-Provide options to either ignore/include the global level settings on export
-Provide options to either ignore/include envelopes/automations on export
This way Shotcut allows for basic audio control, needed to properly create a video with more complex audio layers, but a dedicated DAW with limited video support can be used when one wants to achieve a more complex audio post-production.
Of course ideally would be when shotcut would include a full featured DAW, but as long as that’s not achieved, multitrack export with some options to include basic level control or not in the exported files, will still allow for a great level of possibilities.