miadhg Make sure the EA App and Steam are closed and the EABackgroundService is NOT running in the Task Manager's background processes list. Open [install location]\The Sims 4, here by default for an EA App or Steam install, respectively:
C:\Program Files\EA Games\The Sims 4
C:\Program Files (x86)\Steam\steamapps\common\The Sims 4
Delete the EP21 folder inside. Then open Delta and delete the EP21 folder there. Clear the EA App's cache:
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
Repair the game again, then reinstall R&L and test it in a new save, with your Mods folder still removed.
If that doesn't help, please provide a dxdiag. Click Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop. From there, you can attach it to a reply using the paper clip (Attachment) icon included with the other formatting buttons.