Hi fame-management.nl,
Thanks for reaching to us.
1. Translation
+ In order to change / translate words. Please make sure you synced the strings first before changing / translating WooCommerce, WoodMart Core plugins and WoodMart theme. You can refer to article
https://xtemos.com/docs-topic/theme-translation/
https://xtemos.com/docs-topic/how-to-make-woodmart-multilingual-with-wpml/
+ You are also need to select the language for the backend and theme settings for admin from the admin user profile, please edit the user’s profile and then select the language for that user it will show the same on the backend.
+ Some strings related to Wishlist / Compare / Login & Register page, you can change in Theme Settings > Shop or Theme Settings > My account https://prnt.sc/W8Tt95stG3YC
2. Bundle / Upsell
You can try Frequently Bought Together feature of WoodMart theme https://xtemos.com/docs-topic/frequently-bought-together/, but it isn’t intended to be used for every Product. You can add the FBT Product Bundle to those Products on which you want to add FBT. To those on which you don’t want, you can show Related Products which can be enabled by going to the Dashboard > Theme Settings > Single Product > Related & Upsells > there you can enable it: https://ibb.co/5hsJxfD
Further, if you want to specifically show Related Products on a Product, then you need to edit that Product > scroll down to Product data area > there open the Linked Products sub-tab > in that you can define the Upsells: https://ibb.co/zbFWWTd
In this way, you can specifically define Related Products for an individual Product.
Regards,