Sims 4 Freezes while saving

My better half loves the Sims and has been playing Sims 4 since 2020 with little to no issues.

She often has long breaks from the game, then will play it for days at a time, sometimes pulling Sims all nighters.

Recently, after going back to the Sims again and purchasing a new expansion pack, she ran into some trouble; first with a bit of corrupt CC which was causing the game to crash to the desktop but we fixed that.

Unfortunately, after fixing that issue she immediately ran into another. When working on a lot for several hours, she tried to save and the game said it was saving but stayed in this state eternally without fully crashing the game. This has been happening constantly since the beginning of November and has made the game basically unplayable for her.

After running a few tests, this is what I've found:

• The problem seemed to happen most often when saving in an unoccupied lot.
• It didn't matter what world or lot type it was, it happened regardless.
• The save glitch happened both with and without mods and CC present.
• It happened on a fresh save and on an older save.

Now, my better half has 100gb+ of CC and mods running usually, but despite enormous (and understandable) loading times, she's happily been able to play for hours and hours with no issues. This is the first time such a serious error has regularly occured and it's really affected her enjoyment of the game and is really demoralising.

Is anyone else facing the same issue? I've seen similar threads here and elsewhere about it, but specifically does anyone have any advice for a bug where the game saves infinitely? Anyone been able to identify what causes it?

Thanks in advance!