As far as I know, it has to be approved unanimously, so Turkey can say "NO" and nothing will happen. The point is that ... today Turkey makes demands, sure, but tomorrow it's someone else, or event today itself, except that Turkey is more "dramatic" about it. Who knows what Finland and Sweden actually have to "give" in order to join NATO. That's life, and that's also okay.
Which is BTW similar to what's happening to EU: they realized that some states have too much power in the admission process, so they want to "speed up" the process. Probably they will go for a "3/4" of the members have to say YES. That kind of stuff. Same old, same old.
If I recall correctly, it requires unanimous vote of approval.
Everyone else leaves NATO and sets up NATO2 where Sweden and Finland are members but Turkey is not.
That sounds like a very big and complicated undertaking, both politically and militarily.
Turkey has NATO's second-largest army, for one thing.
Perhaps it's more important to have Turkey in NATO than Sweden and Finland, but I honestly don't know. I hear Finland has a strong army and it's useful to have all of the Baltic Sea countries in NATO.
Turkey's location is incredibly important strategically. They control access to the Black Sea.
Turkey is second-largest based on manpower, right? Time to update that ranking soon: Turkey 775,000 vs Finland 937,000 military personnel available
Because Russia is still the scarier enemy. If the rest of NATO approves, what is Turkey going to do? Leave NATO and accept eventual invasion?