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.
You can lend games on steam ???
Family sharing I presume. I’m not entirely familiar with the scope of the service myself as I’ve only just set up family sharing with my child. But when I did, they had a huge catalog of games in their own steam account as a result.
Yup! Not all, but most. Some with high levels of cheaters block family sharing, like RUST