I don't think it's a matter of availability... those who are interested in the S22/S22 Plus will wait until they are released. And regardless if Ultra model is released before the others one, it's going to be a shortage on the Ultra model.
If buyers don't pursue the Ultra early... expect ship dates to go back months. If rumors are true Samsung is staggering the release of the S22/S22 Plus and Ultra. I haven't did the early preorder for the S22 Ultra... my hands are set on the Fold 4, but I'll be excited for those who get their hands on the Ultra early!
S22 ultra will certainly be a day 1 pre order for me.
Fold wise I guess it depends what the fold 4 provides if I upgrade it or not. I’m actually tempted to keep it another year. I only really use the outer display anyway so if they make the front display wider that’s not a deal breaker. 2 to the 4 will be a good upgrade for you though