Well in today's world (post COVID) all timelines are unknown.
It all depends on the persons situation. If the spouse can do full support for a year, then the K1 is still faster. She needs to look at all aspects based on their situation. If they want to be married and together in the same country, the K1 is still faster. But the K1 has draw backs such as change of status. But there are drawbacks to the CR1 as well. They simply need to know the facts and choose what is best.
What was the deciding factor for my wife and I was the time. Mainly because of Brazilian law and wait times for marriage there and the fact I would need to make a minimum of another trip, which is time off of work as well as the expense. As I stated above, for a foreigner to marry a Brazilian in Brazil there is a minimum 30 day waiting period after you apply for the license. That is na expense most are not considering here. You could get married faster going to a neighboring country, but that has its own complications with the process as well as family.
We were also very surprised on our timeline. Started in April, E-mail for consular interview in July scheduled for August....My immigration lawyer said it would be 9 months.
Now everything is so back logged.
However given the AOS and such of the K1 I went into it assuming I would have to support her 100% for a long period of time. That is the nature of a K1, so if you are not financially able to do that then the K1 needs to be re-evaluated. Even when we did ours the timelines were not given to be fast. We got very lucky. But when you do this you need to plan for the worse since you have zero control of the timeline.