The timeline is the least accessible part of the Shotcut UI. You do not need to use the timeline in Shotcut. It is possible to make single-clip-only and playlist-only projects in Shotcut. I think we should start there. In a clip-only project, you can open a single clip, trim and filter it, and then export it. For this, you only need Ctrl+O to open a file into the Source player. Then, you can refer to all of the keyboard shortcuts under the player section. When you use left and right arrow keys here you should hear little audio blips as long as “Scrub Audio” is turned on in the Settings menu. If you still do not hear the audio, then this feature is incompatible with the format or encoding of some files. In the Properties panel there is a way to convert a file into what I call an edit-friendly format to fix that. Next, Press I to set the start frame, and press O to set the ending frame. Finally, you can export the sub-clip.
Now, you can also do the above repeatedly; but, instead of export, add each sub-clip to the playlist. When done, you can export the playlist, which will concatenate all of the sub-clips.
Initially, the playlist panel is not open, and that is OK. With a clip opened and trimmed, you can press shift+a to add it. That opens the playlist panel for you, but maybe you do not need to do anything else at this time except to export it of course. You can add more to the playlist by repeating everything you have done thus far. You can play the entire playlist by pressing the escape key and use the same playback shortcuts. Press escape key again to return the clip player, which has the label “Source”. Exporting the playlist is simple. As soon as you add something to the playlist, export automatically defaults to export from the playlist. This can be confirmed using the drop-down control labelled “From” in the export panel.
Let me give you a tip about the toggles for the different panels. When you use the View menu or keyboard shortcuts, it will toggle the visibility of the panel. However, the main toolbar buttons always make it visible - not a toggle - and raises the panel in case it is tabbed behind another panel. I just noticed that neither of these methods give focus to the panel. Panel focus is difficult in this UI and for most users. So, Shotcut demphasizes it. However, sometimes it is needed. I guess your voiceover software lets you search the UI and take focus. Each panel does have like a sub-window title, and maybe you can find it that way. This panel title is also reflected in the tab in case the panel is tabbed with another panel.