This was way more confusing than it had to be.
TL;DR: You can lend your digital games to friends & family for 14 days, but both consoles need to connect locally to enable this…(?)
You can’t play digital games you’ve lent out during this time. I guess the point is making it similar to giving your friend a physical game cartridge.
The two weeks are only for sharing across accounts in a family, if you’re using the same account across two devices there isn’t a time limit. You could already play your games on both but before the secondary device needed to connect to the Internet every time you launched the game, and now it’s just when loading.