Every editing tutorial starts with the same advice: learn your shortcuts. J, K, L for playback. I and O for in and out points. It sounds like reasonable advice until you spend three sessions drilling shortcuts and still feel slow.
Here is what that advice misses. Shortcuts only save time when you already know what action you are about to take. If you are still deciding what to do next, no shortcut helps. The speed gap between a beginner and a working editor is almost never about finger speed.
Where the real slowdown happens
Professional editors are fast because they make fewer decisions per cut. They have a clear opinion before they touch the timeline. The deliberation time, which clip to use, where to cut, what the scene needs, is almost entirely eliminated through experience with story structure, not software fluency.
If your first attempt at editing software failed, the shortcut list probably made you feel like you were on the right track. You were not wrong to try. But the gap is upstream of the keyboard. Spend time watching rough cuts, not tutorials, and your software fluency will follow naturally.