Re: game stuck on endless loading screen (only work when offline)
@madebyqq Try disabling Online Social Features, in Options > Game Options > Other. You can load the game offline once to disable this, then go back online.
If that doesn't help, try playing with the EA App in offline mode.
I'd also like to see any errors related to this problem, if they exist. Your dxdiag doesn't list them, but there are other ways to find the info. Hit Windows key-R and enter "perfmon /rel" without quotes, and you'll see the Reliability Monitor: a chart of errors and updates with a column for each day. Today is on the right.
Look for an error that happened at exactly the time of your most recent attempt to launch Sims 4 while online (when it didn't work). If you find one, double-click it to see more details, then copy that info and paste it into a reply here. If you don't see a new error, check back in an hour or so—the Reliability Monitor doesn't always update right away.