Well the thing is they went from a great power, with arguments for them to being the greatest power to an empire facing numerous internal troubles,
They didnt face more troubles than other contemporary empires. The difference is that other empires were not dog-pilled on by multiple superpowers, thanks to the concert of Europe trying to prevent exactly that. I also gave examples with:
-the interregnum prior to massive Ottoman expansion
-The Köprülü reforms
-The tanzimat reforms
I dont know why you guys are hell bent to claim that it was a simple "expansion-> stagnation-> decay" process, when it clearly wasnt.
having lost a lot of land - many of which to rebellion, all during the 17/1800s.
None to "just rebellions". The only successful break-aways are Greece and Serbia. Both of which had heavy involvement by western powers. Imagen: Any nation in that time period is going to have issues when multiple super-powers are dog-pilling on you.
They stood at the forefront of technology in the 14-1600s but were relatively backwards by the time the 20th century rolled around.
No. They lacked money, not technology. The Ottoman army was not run by swords. The Tanzimat reforms brought a f+ck ton of western experts. Society was already shifted towards a legalistic view. Stuff like medicine and science was overemphasized. You had railway projects reaching from Istanbul to Mecca/Medina. You had Beirute transforming from a backwards vilalge to a premier port in the 19th century. One reason why France and UK wanted Ottoman territory, was precisely not because it was some backwards place, but because they were equally involved in modernizing large parts of Ottoman society, the investment of which they wanted to secure.
This obviously doesnt mean that the Ottoman Empire had british standards, far from it, but various urban centres were not lacking behind. Most definetly not Istanbul. The Ottomans were obviously not a beacon of innovation, but it wasnt the 3rd world country, you are making it out to be.
Mind you, the WW1 entrance is preciselys because of this. Ottoman war-supporters smelled an opportunity to get away from this nonstop dog-pilling by France/UK/Russia. The generals did not believe that they were lacking behind technologically and were confident that they could in fact muster great power, if the efforts are focused on a single great power. Something they proved in Canakkale, Iraq, Medina and to a large part in the Levant. It makes no sense for the british to lose in Canakkale, if the Ottomans were "technologically behind" or were "backwards". That is a nonsense take.
The Tanzimat reforms was an attempt (fairly succesful) to revitatlize a country that had significantly stagnated and fallen behind other European powers since their peak for example.
Overall, leading a large empire (before information age) necessitates decentralization, which breeds a lot of inefficiency and corruption over a long period of time.
The core Ottoman territories that were directly controled continued to be directly controlled. Ottoman control over the Levant or the Balkan didnt decentralize. I dont even know where you are getting this from. Areas like Egypt, Iraq, Hejaz, the Maghreb were decentralized, but they were decentral all along.