Live mode lag

sparklebright9​ is there any furniture, etc in the household inventory in Build mode? A full household or personal inventory can cause a massive lag. But I'd also recommend clearing your library as much as you can I keep mine mostly empty. How many save games are you running? I never run more than 3 on Xbox Series X and I had 2 on Xbox Series S. I'd go into Other Households and clear some Townies too. If you have hundreds of them I've found it causes massive issues. I clear some daily as there are a lot being generated currently especially after travelling to public lots. It's also good practice to clear the personal and build inventories of previous Sims and households. It's especially important to manage that game storage on Xbox, I was given that advice by Xbox Support.

I'd also try powercycling the console. Switch it off with the Xbox button on the front for around 10 secs until it's shut down completely and the light stops flashing. Unplug the power cable to completely reset the power supply. Wait at least 10 secs then plug it back in. Switch the Xbox on with the power button.

You can also clear your locally saved data and sync up with the cloud again by selecting Sims 4 on your console home screen using the menu button (3 lines) go to Manage Game and Add-ons>Saved Data. You'll see 2 sets of data, pick the set next to your gamertag/username and select delete from console only (this step should be carried out while the game is not running). Then immediately load up your game and it will sync up with the cloud and retrieve your data. That's another tip I got from Xbox Support and I do this very regularly and especially if I'm having issues.