4. Download the games onto the Xbox using my kid's Game Pass, then switch to my account to play them.
Set your kid’s account as the “home account”. Then you can just download while logged in as your account too.
This is how game sharing works. I set my nephews Xbox as my home Xbox years ago for Xbox live and now game pass. My account is never logged in on his console unless I’m there. Then of course any game he buys I get too since my Xbox is set as his home Xbox.