Home XBOX Concept

In order to be able to share games, you will need to make your Xbox as a home console following the steps mentioned here Designate a home Xbox | Xbox Support

Please keep in mind, things such as DLCs, in game account rewards or reward points in general are not part of the home sharing

concept; therefore, this will only be visible or linked to the main account.

It's simple, on your home box you not need to login in account with games to play they. Someone from you family can login and play all your games. So, home box is not a family concept

Back in late 90s, Nintendo tried such concept via expansion slot. 17 years on, no one tried to revive it. Considering the next Xbox may be the last home console, I doubt it'll make a comeback.

Xbox has the home console concept. If the account that set the Xbox as the home cosole has the game pass, all accounts connected to the same console can use it. On PC there is not something like the "home setting" for console, so the owner of the pass
has to download the game since he will be the only one recognized as having the pass for PC active, so the info you were given is correct.

The closest thing I can point out for you is "Xbox Gamesharing", but it's an entirely different concept of sharing compared to PS4's Share Play.

You first designate an Xbox One as the "Home" console, and you can then share your entire digital game library (as well as your Gold subscription) with anybody who
logs into your Home console.