Weather lag + computer specs?

@4aad3afd4a94c4e9  Adding more RAM only improves performance if the apps in question are using most or all of the existing memory.  If your system never calls for more than, say, 12 GB, then having 16 GB installed is sufficient to avoid any performance-related issues.  I don't know how you use your computer and can't tell you whether you'd get any benefit from more memory in general.

What I can say is that Sims 4 alone won't be improved by installing another 16 GB RAM.  Even an extraordinarily complicated save can only require about 8 GB to run, at the most.  The only way for a save to use more is if it has some resource-eating bug or glitch, and in that case, the save is toast on any system; the only question is how quickly it freezes or crashes.

Still, if you want to install more memory and the prices are comparable, there's no reason not to do so.  Just understand that it's not going to help Sims 4 unless you heavily multitask while playing.

A clean boot is not a clean Install of Windows.  "Clean boot" means disabling all nonessential services and restarting the computer, so that nothing is running other than what is minimally required: Windows itself, critical drivers (graphics, sound, etc.), and whetever you choose to open in that session.  It's the best way to find out whether some other service is interfering with the app that isn't running properly, in this case Sims 4.  And even a clean Windows install will quickly accumulate a pile of random services that don't strictly need to be running at any given time.  So please try the clean boot and let me know what happens.

Thanks for the CBS log, but it's not necessary here—sfc did its job.  The only concern would be if sfc reported that it found corrupt files and was unable to repair some of them, in which case further investigation would be required.