Eliminating inter-service conflict? You'll have to put all military aircraft (except maybe ships' floatplanes) under one service, like the RAF or the Luffwaffe.
One has to knock heads together and have a "joint operations" concept and a unified theater commander way of doing things and a TASK FORCE centric way of thinking. Lumping passengers together and shuffling chairs on the Titanic does nothing except drowning everyone in chaos. SOMEONE (singular) has to be in charge of the task/mission. To show how difficult it was for the Americans (as an example) to learn this fact, it took four years of their civil war before they figured out the unified theater command setup and task oriented thinking. Before ABRAHAM LINCOLN invented it, based on how he saw the western department evolve by ad-hockery the Union army and navy worked at cross purposes. Then Lincoln solved that one by presidential decree that the navy in the area would do what the army general in command of a land operation told it to do or else. Things ran more smoothly in 1864. Grant could move fleets to where the army needed them, like say to meet Sherman in Savannah Georgia.
That was forgotten in the Spanish American War in Cuber (Not a misspelling, McKinley might have had a speech impediment, as well as an inability to read maps.) and remembered in the Philippine Islands when Merritt told Dewey what, when and where to shoot the place up after the army got there.
World War I was another loss of memory. Pershing did not play well with Foch and Wilson was too moronic to politically figure out why the AEF was not getting it done. (Pershing was a tyro at handling his own generals, too.) WW II, now the bomber barons showed up and it was not until Eisenhower knocked their heads together Three Stooges fashion (His chief role actually, for which he is NEVER given credit.) (Add the British army, too.) that everyone operated on task and became mission oriented. It took THREE YEARS to figure it out in Europe (Five if you count the UK's RAF, RN and British army shenanigans and Mister Churchill before Alan Brooke sorted them all out.). Out in the Pacific, PACFLT (A compromise between Marshall and King after FDR knocked their heads together.) drew a boundary line and gave MacArthur a playpen to fool around in. It was a critically important playpen and the navy had to do what "The Great Thespian" ordered within it, which had good effects; (CARTWHEEL) and bad effects (COMSUBSWPOA) (screwed up submarine campaign), and really TERRIBLE effects when the two theater commanders tried to joint operate (Leyte Gulf, MacArthur and 7th FLEET handled the landings, Nimitz sent Halsey and 3rd FLEET to fight the naval battle.)
It has been my contention that if the MacArthur of 1944, who by then had a fairly good working knowledge on how to use a navy in an amphibious operation, had been given overall command, then SAMAR would never have happened and Kruger would not have had to reposition artillery he needed to support the drive inland off the beach on the good chance he would have to duel IJN battleships in San Pedro Bay. Seriously if you want a monumental German style Mil-op screwed up by divided commands, inter-service jealousy and almost Japanese-like military-political INCOMPETENCE, do a deep dive into Leyte Gulf. Remember, when Halsey hared off and left Kruger wide open to attack, it was Kincaid, Oldendorf and Sprague... MacArthur's admirals of the 7th FLEET who won the key engagements and naval battles.
Korea... Inchon. MacArthur has all the reigns and those military horses, army, navy, marines and the brand new air farce all harnessed and on task and mission oriented. Now later, "The Great Thespian" screws up and that is the DOWNSIDE of unified theater command, but you can fire the old guy, put in a new guy and get back on mission a whole lot faster and stay task oriented effectively.
Want to know how Vietnam and both gulf wars were screwed up?