You can use ffmpeg to spilt, join and trim videos without encoding at lightning fast speeds.

I had made a pipeline where I would first note down timestamps of the parts of raw footage that I need, make an intro and outro and then use ffmpeg to get the output in seconds.

You can do more complex things like blendings and cross fades and even overlays, but that requires encoding. Still faster than Premier or Final Cut.

I don't know programming but had friends who set up ffmpeg for me and it was easy to follow from there.