Yes, if you enable the Catalog mode option, all add to cart buttons and variations selects would not work. You need to disable this function first. As for the problem with the plugin, we can’t check it without your website access.

You can translate/rewrite all theme and plugin texts via PO file in WordPress. Here is a video tutorial that should help you translate your website texts with a Loco Translate plugin https://www.youtube.com/watch?v=D3NsDdMzsls&list=PLMw6W4rAaOgKKv0oexGHzpWBg1imvrval&index=3

Please check the video tutorial to see how to save the translation file correctly. You can remove the plugin and translations would remain. Also, translations would remain after each theme update.

Best Regards