I had multiple dealers tell me that there was a 2 month hold on orders due to the initial production of the eTron GT. I have no idea if this is accurate/true but that's what I was told. I was told this about 2 weeks ago so I would check back with dealers in about a month or so to see if perhaps the window has opened again.
On a similar note, I thought 2021 might be the last year for R8s but that is pure speculation on my part given that pre-facelift was 2016-2018 and facelift was 2019-now (2021). Not sure how Gen1 timeline compares (6 or 7 years total?) but something to consider as well.