Re the Dock: it may not be easily discoverable, but you can resize the Dock by hovering over a vertical bar between icon groups, then dragging up and down. Hold down the Option key to snap to (what I presume is one of a number of) unscaled icon sizes.
One of the first things I do on a new install (as well as turning on the Finder status bar) is option-clicking on the Dock and shrinking it down by one step (or maybe two on a 13" MacBook).
The option key won’t snap to the unscaled icon sizes. The unscaled icon sizes are just too far apart—there’s 48 px, but the other sizes are powers of 2.
One of the first things I do on a new install (as well as turning on the Finder status bar) is option-clicking on the Dock and shrinking it down by one step (or maybe two on a 13" MacBook).