Britain was actually -initially- quite selective in which colonies it went for - most of its empire clustered around straits, capes, and river mouths.
Its African policy - in which it eventually did engage in a giant land grab - was a case of mission creep stemming from its desire to control - of all things - Egypt and the Red Sea.
Book to read is Alice Denny, Ronald Robinson and John Gallagher, -Africa And The Victorians-. It’s actually a cautionary tale of how a sea hegemon can wash up on land.
What made the British Empire the dominate naval and commercial force in the world was not controlling all the land masses on the globe, but controlling the key maritime chokepoints.
English Channel, Gibraltar, Malta, Suez, Cape of Good Hope, Aden, Hormuz & Singapore.
We are learning that lesson again today, as maritime chokepoints are now being contested.