A "Russia doesn't collapse in 1917" scenario is almost certainly easier to pull off than a "Whites win the Civil War" scenario. The Whites were outnumbered, outgunned, and internally divided; it would take a miracle for them to seize control (and even that would probably just lead to another round of civil war between the various White factions).
On the other hand, if Russia can just stave off collapse, Germany is going to collapse fairly soon itself. The British blockade is literally starving them to death; every day the war continues is a day closer to total collapse.There's a reason that Germany, by 1917, was willing to take all sorts of crazy gambles: actively inciting a Communist revolution in a neighboring country, restarting unrestricted submarine warfare and risking US entry, and the all-out Spring Offensive; they knew that if they didn't get lucky soon, they were doomed. The remaining Central Powers were already on the brink of collapse: Austria-Hungary had been more or less crippled since the Brusilov Offensive, the Ottomans spent 1917 being driven out of the Sinai and Palestine, the Allied forces in Greece were threatening Bulgaria.
Assuming the Russians manage to beat back the October Revolution, they will certainly prioritize restoring control over their pre-war territory. Without the need for a cordon sanitaire to keep the Soviets away, the rest of the Entente have no interest in supporting independence for Poland/Finland/the Baltics/etc.
While the full Sevres terms probably won't go through, more of it will. In particular, you almost certainly do see an Armenian state carved out of what is now Eastern Turkey (either as a Russian "mandate" if we get something like the League of Nations mandate system, or merely a more traditional nominally-independent Russian puppet state if we don't). We might see a Kurdistan too. The internationalization of Istanbul almost certainly doesn't stick, but I expect that you do see significant modification of the terms of the Straits Convention to allow Russia greater access to the Mediterranean.
You still get a partition of Austria-Hungary, but Galicia probably goes to Russia as well (either directly or as another puppet state), to give a more defensible border along the Carpathians. Not sure how Germany shakes out.