How to assemble very fast in Adobe Premiere 2019
The only keys I'm using here are I (mark in point) O (mark out point) clicking with mouse (make sure the clip you're marking ISN'T selected; I know, it's weird) and ; (insert. Insert copies the marked section only, into your timeline, as you can see at the end of this video)
Computers with CUDA graphics cards (generally Windows, not Apple) will slice through footage like this very fast, as well as enabling maaaany realtime effects (no rendering required - instant preview)
I'm also using the maximise panel shortcut and I've enlarged thumbnails to full size. Check out Keyboard shortcuts to customise the keys you use a lot.
Finally, I'm using a 4K screen (the rest of Premiere is off-screen, to the right, on my laptop 1080p screen) I thibk 1 x 4K screen is the minimum to do efficient editing on in Premiere, because there's so much stuff on screen.