loislanenetwork That's very odd. Do the crashes happen if you just leave the game paused, or if you let the clock run but don't interact with it (i.e. your sims are doing their thing without input)? And I'd like to see the types of crashes you're getting. Click Windows key-R and enter "perfmon /rel" without quotes, and you'll see 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 Sims 4 crash. 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.
Please post the most recent three or four crashes, or just one example if they're all identical.
Please also let me know if you're able to connect your desktop PC to your phone, set as a mobile hotspot and using data rather than your home wifi. Your computer does have a wireless LAN driver installed, and this wouldn't use much data if you were just connecting to the EA App and playing, but I know not everyone has this option. The reason I ask is because it kind of sounds like the game is trying to connect in some way, and failing, and crashing as a result. Why this happens more often offline than online, or frankly why it happens offline at all, is a mystery.
One other test you can do is to disable Online Social Features, under Options > Game Options > Other. This is supposed to be inactive when the EA App is in offline mode, but perhaps that's not the case.