The British Empire has kept the ottoman empire alive for centuries and it is an evil thing that they do.
The Americans carried on the policy of keeping it alive by getting Turkey into NATO and for the same reason, keeping the Russians in check. This is what great powers do, they secure their own perceived interests and if they have to shaft lesser peoples or countries to do that, well, that’s just tough, neither the British Empire nor the American hegemon was or is any different.
Historically speaking you are right. The Ottomans would have been gone by 1820 and Constantinople would be Christians again if not for the UK playing games