attentionboar Does this happen in a new save too? Please test to find out whether only your main save is broken or the pack in general.
If the content doesn't work in a new save, clear the EA App's cache:
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
Close the EA App and kill the EABackgroundService in the Task Manager. Open [install location]\The Sims 4, here by default:
C:\Program Files\EA Games\The Sims 4
Delete the EP04 folder, which corresponds to Cats & Dogs. Restart your computer and reinstall the pack, then test another new save.
If only your main save is broken, or it's still broken after the above (but the newest save is fine), you may need to do this (Method 1):
https://sims4.crinrict.com/eng/2022/06/world-appears-twice-on-world-map/
It's a workaround for a slightly different issue but should help you as well.