I'm pretty "fluent" with navigation shortcuts, things like Ctrl/Alt/Shift combined with arrow keys, PgUp/PgDn/Home/End etc. and I do use them extensively. And yeah, constantly switching between the keyboard and mouse with my right hand is a bit annoying.
But still, in many cases, using the mouse is just faster. For example, jumping to a specific position in a source code file, scrolling and clicking gets me there much quicker than navigating with the keyboard alone.
(This is also one thing I really hate about using terminals: you can't just click to move the cursor quickly! Editing part of a long string without spaces is a pain in the ass, and it's something I have to do surprisingly often.)
When it comes to shortcuts, I prefer one- or two-key combinations whenever possible. Three-key shortcuts, however, depend on their layout: many just aren’t that convenient. Sometimes I’ll just click through the menu manually, even if I know the shortcut.