I started a very similar post. DO WE NEED A HI CAPACITY PISTOL! more or less. It has gone on for over 14 pages.
Over the years, my Glock 19 has become rather big! So downsizing to the New purchase, a Glock 43X and a spare mag has happened. Total 21 rounds of 147g 9MM federal.
From the draw, 11 rounds. It will be enough, or it will not. And I have always considered the extra magazine, more of a just in case, as in a malfunction, than a gun emptied situation. Coming with a set of Ameriglow night sights, big plus.
But always being armed a good thing.