Make Contao FE Modules multilanguage (jumpTo, ...) and provide Multi-Language Containers to reduce the Amount of Themes, Page-Layouts and Modules.
Multi Language Modules
This Contao 4 Module provides the ability, to reduce the ammount of modules beeing used in your installation. You can create a "Global Module" and select a related Frontend-Module. Then select what fields are language aware and edit this fields for each language.
So more need to create a Module in a Theme for each language (e.g. jumpTo Pages).
This area is only editable for Administrators
Global Layout Sections
You can create a Layout Section and assign a content type to it. Then you may create multiple variants of this CE Element for your used languages.
Then grab the insert tag and put it in your template (fe_page or html module in your theme).
Why? You can have 1 Theme for a Multi-Language Site with language dependend Content.
E.g. on the your Website you have a different header image in french then in english. If so, this module is just right for you.