Hi there @5sb5lyfii896 I've had these problems before and these tips helped me.
I cleared all items from the inventories of previous households, both personal inventory and household inventory/fridges. I cleared as much as I could from my Library. I also cleared non essential townies from Other Households, in fact I do that every few days. I don't know if you have For Rent but in particular I'm getting a lot of new Townies generated with Tomarang. I'm constantly clearing some out. If Other Households gets too packed my game is really slow and unreliable. Plus the more packs you have, the more characters/content and on console it can really destabilise the game without careful management. Also check your Sims total in your households and check it's not too close to the Sim total limit you have set.
You can also go to Manage Game and Add-ons and where you see your saved data, you can clear the smaller amount of data next to your gamer tag (see attachments), clear just from your console (not delete everywhere). Then immediately load your game, it will then tell you it's doing a data synch. Let the data synch complete and the game will start.
Keep clearing inventories when switching households and keep checking Other Households as you play. Check how many Save Files you have. On Xbox One/Xbox Series S and now Xbox Series X I run a maximum of 3 saves. Right now I run 1 plus a backup save. I had problems running 3 on Xbox one.
It's a frustration that we can have loads of space on our consoles but the game can still struggle. I've been through it all with Microsoft Support too. They told me the sheer size of the game can be a factor.
I hope something here helps but just ask if not and good luck.