Why didn’t Russia try to conquer Constantinople and surrounding territories after the Ottoman Empire collapsed?
During the 1768 — 1774 Russian Ottoman war , Russia was close to conquer the Ottoman Empire
Russia conquered Crimea and kicked the Ottomans out , defeated them in Caucasus , and totally destroyed the Ottoman navy in 1770 during the battle of Chesme
a revolt occurred in Greece and Russia formed an alliance with the Mamluk of Egypt Ali Bey al Kabir who kicked the Ottomans out of Egypt and marched towards Syria with Russian support
Russia bombed and occupied Beirut , at that time the Ottoman Empire lost all of it’s Arab provinces as Iraq was ruled by Kulmnd Mamluks and Syria was falling as well , Russia had the Ottomans on their knees , but Britain , Austria and Prussia saved the Ottomans and prevented Russia from conquering Constantinople
Russia tried again in 1791 and 1878 and was too close but the Western powers feared a very powerful Russia.
John Jafar on Quora