@faye87429
One thing that would be good to know is if you are running on a Mac or PC and if you are running on a laptop or desktop.
Yep, based on what you said, it's probably a mod issue. One thing you need to look at is if all your mods are current and they have either been cleared or updated since Lovestruck was released. I know several you listed have been updated because I use them. MCCC, UICheats, and More Columns are good if you have the latest. Idk about the others you list. Wonderful has been updated now too btw.
In addition to your mods, you should take a look at your CC if you use any, particularly the older stuff and especially anything that you used before the devs added a similar item to the game in later updates and packs. Things like custom nails and now eyelashes, especially the 3D ones, could be conflicting and slowing your game down.
One thing you probably ought to consider doing if you have a lot of CC is to winnow out and remove stuff you don't use very much if at all. From personal experience, it can have a huge impact on your game performance. Just as an example, when I did it, I ended up removing about 2/3 of my CC along the way. I was one of those people who pretty much anything I though looked neat and added it to my game. Over time, I had a huge amount of CC. A lot of it was stuff that I never used. I also found a bunch of CC that had been broken from the start. So, after suffering with huge lag for about a year, I finally bit the bullet and went through everything I had, one item at the time with S4S and ended up getting rid of all my broken files, almost all my build CC and about half of my CAS stuff. Of course, you then have to go through your lots and sims to fix some things where you used CC that you'd removed. You'll also need to delete the localthumbcache file. It was really worth it when my game lag went away, and my game ran so smoothly even though it took me a couple of RL months to do.
You've said you deleted the localthumbcache file. If you don't know though, you should delete that file every time you delete or update any mods and/CC. It's not as important when you just add something but it's good practice to delete it anytime anything changes in your mods folder just to make sure everything is actually showing up ingame.
Hope this helps.