Constant lags despite high end PC.

Francoisf30​  Please test a new save, with fresh sims and no content from your library or the Gallery, and your Mods folder removed as well.  This will give a reasonably-good baseline for performance.  Even if you'd never play without certain content, please let me know how the game runs in this context.

Please also 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.

You can improve performance to some degree, especially when moving the camera, with some .sgr edits.  Please see this post for more information:

Camera movements very choppy since BH patch | EA Forums - 12185589

The most important value is the LOD distance, as in, when the game switches between different levels of detail.  The higher the values, the further out you have to be before getting a lower LOD, and therefore the less switching, which is the source of drag on performance as far as this part goes.