This hasn’t been possible for years now unfortunately. I mean, you can extract all the certs you want with Lockpick but they won’t get you anywhere. It’s been like 7 years since then so I don’t recall the name of the tool that was used for downloading stuff. Could have been this.

Back in Wii U / 3DS days Nintendo didn’t protect their CDNs at all, no authentication. It was quite funny on 3DS because if you bought something on eShop it was stored as a small file on your end so you could just copy those „ticket” files and then go to eShop and have an experience like a paying customer.

When Nintendo finally realised they blocked comms from non-Nintendo devices but you could still extract a cert and use it to authenticate. Most people used shared ones because it was assumed they’d be burned sooner or later. When those shared certs became harder to get I tried using my own assuming they get burned because so many people used them. I was wrong and burned mine too very quickly.