I had the same problem with Cuphead but I was able to do something to get it to activate, but don't know exactly what it was. I know I went into the eShop and selected the game there to see if there was some kind of "activate" button even though I had already pre-bought it, and I think I also rebooted the Switch. In any case, the game became active at some point during the process and I was able to start playing.
I heard some comments saying that many indie games only release at 9 AM pacific, so I'll check it out again in 10 minutes, but alternatively I have thought of rebooting the console. Either way, yeah, I'm most likely playing it on PC in the end. I don't regret buying it on Switch because the game deserves my money and I wouldn't have bought it anywhere else, and I'm also hoping they improve the performance with updates, but... yeah.
Edit: hmm, random comments were right, it did activate now. Well, I can't play right now any way, but it's good to have that concern out of the way at least.Last edited by mZuzek - on 25 June 2019