It takes 6-8 weeks for the voice to sound fit for daily use. But then a couple of months more to loose the hoarseness - the voice exercises of Yeson help, starting at week 8
Voice surgery is not magic - the results of Yeson on Youtube are often great, but one has to admit that they are not randomly selected. So please if you consider the surgery, do not overstretch the expectations - it probably will not be as great as Jennys voice (who did the surgery at a 50% reduction of the vocal chords, giving her more increase plus she did a lot of training) and it will not be done with doing the surgery but require some additional effort of learning the voice. One patient was severely disgruntled because she imagined to just go there and get a voice like Jenny without any more efforts and it did not happen...
Regarding other options than Yeson - here in the forum there are at least 2 more options disussed - Remarcle in Europe and Haben in USA. They do things a bit differently but results seem to be quite good as well, mostly.
Speech training makes some sense - its a mixed bag doing a lot of it pre OP as half of it can be applied, the other half has to be unlearned again. So if one plans on doing the surgery anyways, I think it actually makes sense to first go for the surgery and then do the voice training with the new improved voice that makes it a lot easier. If one can imagine to avoid surgery, it makes sense to first try training as in many cases it can give acceptabel results as well, in some cases even good results.