I use Shift+click to even out protruding blocky shapes. Maybe I am wrong, but it feels that it thins out things too much for one click, and changing the Strength does not seem to affect the amount of its thinning out. Can I make Shift+click more subtle and delicate? If not, what can I use other than shift+click?
Shit+click is an immediate shortcut for smooth brush, so while holding shift down you are calling the smooth brush. Changing the smooth brush settings to your desire should help.
And you are not wrong doing it like that.