My sims either won't follow a command (just stand there) or they "do" it without actually moving. For example, they will go to sleep without getting into bed. I've linked to a video to better explain...
Ideas
Did you never use mods or remove them ?
Have you tried a game repair yet ? It sounds a bit like an issue that was fixed a while ago.
I’m having the exact same issue, it’s racking my brain. I’ve tried repairing the game, mod cleaner/reports, uninstalling, taking my mods out completely, deleting useless files. I don’t think it’s the father winter issue either, although I’m having similar symptoms. Im trying to avoid deleting my save but if I must sacrifice it I will. :(