I have a 2013 Boxster (6MT) and a 2019 Golf R (6MT) on my side of the garage. I find them to be a very matched set. The 981 has the better transmission and generally sounds/feels more alive and engaging than the R. The R feels quicker and more refined than the 981; and the R corners well enough that I doubt it would have trouble keeping up with the 981 on a really twisty road.
I’ve occasionally thought about selling one of them to simplify the parking situation, but I can’t decide which one to sell. The 981 in my spec is irreplaceable and the R is just a much better fit for 80% of my driving. I doubt the OP would miss the Boxster too much. The R or GTI would probably be the perfect alternative.