how to cure sick sim without game pack

Have you tried turning testingcheats on and shift clicking on the sim and clicking Reset(or debug I forgot which one shows up). It usually works for me.

I agree. Delete the mods from the folder on your game/machine:  Go to Documents > Electronic Arts > The Sims 4 > Mods
Plus delete the cache: https://sims4.crinrict.com/en/2014/09/delete-cache-files/

You could restore to a previous game this way if the game play was messed up while dealing with the mod - but remove the mod first: https://help.ea.com/en-us/help/the-sims/the-sims-4/how-to-restore-a-previous-saved-game-in-the-sims-4/

For future reference, once you have it cleared up and have a clean game version, start backing up occasionally. If you have a backup you can roll back to a date/version without the issue and not completely lose your game. Go to Documents > Electronic Arts > The Sims 4. Right click on the file "The Sims 4", copy it. This file is your backup of your game saves, etc. You should save a copy of this folder occasionally in case your game or computer crashes. Save it to an external drive. That way you could add this folder into a fresh install and recover your lost game should you need to.