I've spent a long career getting good at Linux. Real good. But I'm only human. Over the decades, the number of how-tos, wiki pages, Linux distros, Linux kernel source, other programs documentation and source; all of that which I've ingested and used in practice and gotten good at, doesn't hold a candle to AI having been trained on every single last one of them. The solution to your apt/Vivaldi problem is easy: install Claude code, and paste in the error. Hit ctrl-o to gain insight on how it fixes it.

You used to be able to charge a decent hourly consulting rate to do some Linux, but because Claude code is so good at it, there's no market for that anymore.

(for one, your URI is wrong, resulting in apt looking for .../deb/dists/stable/dists/stable/Release )