I am currently reading the excellent Remembering Pinochet's Chile: on the eve of London 1998 by Steve Stern. The book treats at some times the relative disparity of repression conduct between the regions of Chile after Pinochet's coup. Chile being a very vast country, with complex geography, I was kind of "impressed" by the homogeneity of the coercion in the whole country.
My question is, are there past cases when the newly formed government (following a revolution or a coup, or any kind of overthrow) was willing to let loose of part of the territory, knowing they could not effectively rule this fragment of periphery, to focus on consolidating the urban power, the presence in the capital (or another big city)
I don't think this is quite the example you're looking for but Muhammad Ali Pasha in Egypt initially claimed and controlled much of the Levant and the Hejaz in addition to his core territories in Egypt. When he went to war with the Ottomans to prove that dominance by force he was forced into a ceasefire by the British who threatened the supply lines of his army.
The trade was to give up everything outside of Egypt (and Sudan) in exchange for permanent, hereditary, de-facto independence in Egypt.
It wasn't intentional but the "Egyptian-ness" of these boundaries has proved beneficial, and I think it could be argued that Egypt is far more of a natural nation-state than many of its neighbors, historically speaking.
Edit: typo.
When Enver Hoxha came to power in Albania he got released Albanian claims to parts of Yugoslavia in order to consolidate his power in Albania and not have to deal with a foreign conflict.
Russia/the Soviet Union gave up vast territories to the Central Powers, as well as giving independence to a whole bunch of new countries immediately after the October Revolution (countries which Stalin mostly integrated into the USSR before and during WW2).
Source:
Will E.H. Carr's The Russian Revolution from Lenin to Stalin do? It's a good book and I never see it mentioned in these threads.
This was attempted unsuccessfully by Belgrade during the claps of yugoslavia.
They acepted Slovene independance but tried to hold onto the other republics.